Islam does not oppose planning for the future. One’s caring about the future and planning a career does not contradict at all with the belief that it is only Almighty Allah Who possesses absolute knowledge of the Unseen. Human knowledge of the future is relative, based on certain premises in one’s life; it is not absolute as the divine one is.
It is an Islamic teaching to plan for things one thinks about doing and to balance the pros and cons before embarking on them. Islam, in fact, refuses doing things at random. The Prophet (peace and blessings be upon him) set excellent examples that showed the importance of planning before taking any action. This was obvious in the plan he (peace and blessings be upon him) put for migrating from Makkah to Madinah, in his interest in the conflict between the two superpowers (Persia and Byzantium), in his sending messengers to the rulers of the world to call them to Islam, etc. This shows clearly that the Prophet (peace and blessings be upon him), with all the confidence he placed in Almighty Allah, was aware of the importance of systemized planning for future steps.

The eminent Muslim scholar Sheikh Yusuf Al-Qaradawi states: It is one of the collective duties (fard kifayah) nowadays to acquire what is called future sciences, this is, to envisage and seek future progress by using science and information technology in meeting the challenges and major transformations the world is undergoing in social, cultural, economic, and environmental dimensions. It is not lawful for Muslims to be isolated from the development and progress reached in such sciences.

We are to bear in mind that this has nothing to do with predicting the Unseen. It is Almighty Allah alone Who possesses an absolute knowledge of the Unseen. As for human knowledge about the future, it is a relative one that Almighty Allah has enabled mankind to acquire in the framework of the laws He Almighty has set in this world.
Knowledge in this regard is like forecasting the weather, which depends on meteorological data, such as the direction of wind, clouds, etc.
Planning for the future is a scientific approach that depends on scientific methods such as statistics and careful calculations. It seeks to accomplish future goals by putting a systemized plan that enables one to meet the resulting challenges.
Unfortunately, there are some people who depict the religion of Islam as being opposed to the idea of scientific planning for the future. This, in fact, stems from the historical conflict between science and religion [in Christian theology].
By contemplation, one can realize that the very idea of religion is based on planning for the future. This is to say, a pious person leads his life focusing on a future goal, that is, to be one of the winners on the Day of Judgment. He does his best and plans his life according to a certain path so as to reach that end and gain Almighty allah’s pleasure.
the story of Prophet Yusuf (Joseph—peace and blessings be upon him) gives us a clear lesson that shows how important planning for the future is. According to the Glorious Qur’an, Prophet Yusuf (peace and blessings be upon him) set a fifteen-year economic plan in order to meet the drought crisis. He (peace and blessings be upon him) knew, through the knowledge of interpretation of dreams that Almighty Allah inspired him with, that drought would afflict the region at his time. So, he suggested an economic plan to face the crisis and he was responsible for carrying it out.
allah Almighty says in this regard: [(Yusuf) said: ‘For seven years shall ye diligently sow as is your wont: and the harvests that ye reap, ye shall leave them in the ear, except a little, of which ye shall eat. Then will come after that (period) seven dreadful (years), which will devour what ye shall have laid by in advance for them, (all) except a little which ye shall have (specially) guarded. Then will come after that (period) a year in which the people will have abundant water, and in which they will press (wine and oil).) (Yusuf 12: 47-49)
Planning and Putting Trust in Allah
Some people think that planning for the future contradicts with one’s having to put all one’s trust in Almighty Allah or that it contradicts with one’s belief in Allah’s predestining all events. That is why they believe that Islam does not accept the idea of planning at all, let alone encourage people to adopt it in their lives.
Contemplating Almighty Allah’s Book and the Sunnah of His Prophet (peace and blessings be upon him), one finds that they refuse randomness and arbitrariness in doing things.

Furthermore, the Prophet (peace and blessings be upon him) made it clear that putting all one’s trust in Almighty Allah does not mean that one leads one’s life randomly, without following a system or taking the required steps to do things.
It was reported that a Bedouin went to the Prophet (peace and blessings be upon him) and left his camel in front of the Prophet’s Mosque. Then he asked the Prophet (peace and blessings be upon him) which would be more correct: to tie the camel to a post, or to leave it untied, depending on that since he had trust that Almighty Allah would guard it for him? The Prophet (peace and blessings be upon him) answered him: “Tie it, placing all confidence in Almighty Allah” (At-Tirmidhi, Ibn Hibban, and Ibn Khuzaymah).
Refuting the opinion of those who said that taking precautions is a sign of one’s lacking trust in Allah, Imam At-Tabari, an eminent scholar, said:

In fact, taking precautions on doing something does not mean that one lacks entire confidence in Almighty Allah, nor does this contradict with one’s belief that Almighty Allah has predestined every thing. Taking precautions and all required steps on doing things is a teaching from Almighty Allah and an act of Sunnah, too. The Prophet (peace and blessings be upon him) would put on two armors and a helmet on going to battles, and would locate archers on the passes of mountains and hills to protect the back of the army. He (peace and blessings be upon him) also told his companions to migrate, first to Abyssinia, and then to Madinah [to escape the torture the polytheists in Makkah.] He (peace and blessings be upon him) also migrated and took all precautions required in that regard. For example, he took the provision he would need with him, and left his family sufficient provision, too. Mind that he (peace and blessings be upon him) did not say that Almighty allah would send down provision on him or on his family from heaven. (Of course Almighty Allah was able to provide him then with anything, and he [peace and blessings be upon him] was worthy of this, [but this did not happen, so that Muslims could learn the lesson of the importance of taking precautions.]) (Ash-Shawkani in Nail Al-Awtar)
Planning for the Future in the Prophet’s Biography
Reading the biography of the Prophet (peace and blessings be upon him), one realizes that he (peace and blessings be upon him) would prepare for everything before embarking on it. He (peace and blessings be upon him) would consider all possibilities and take all precautions required, and this was never regarded as being in contradiction with the entire confidence he (peace and blessings be upon him) would place in Almighty Allah.
For instance, he ordered his Companions to migrate to Abyssinia in order to escape the torture of the polytheists in Makkah. The choice of Abyssinia then was not haphazard. He (peace and blessings be upon him) was aware of the geographical, religious, and political background of Abyssinia and thus was sure it was the most proper place for the oppressed Muslims to head to.
this shows us, also, that the Prophet (peace and blessings be upon him) and the Muslim community then were not isolated from what was taking place in the world then, despite that means of transportation were difficult then.
This was also obvious in the attitude of the Muslims toward the conflict going on then between Persia and Byzantium (Eastern Roman Empire). [The Muslims sympathized with the Byzantines, for they, too, were followers of a heavenly Book.]
Allah Almighty says in this regard:
The Roman Empire has been defeated in a land close by; but they, (even) after (this) defeat of theirs, will soon be victorious within a few years. With Allah is the Decision, in the past and in the Future: on that Day shall the Believers rejoice, with the help of Allah. He helps whom He will, and He is exalted in might, most merciful. (It is) the promise of Allah. Never does Allah depart from His promise: but most men understand not. They know but the outer (things) in the life of this world: but of the End of things they are heedless. Do they not reflect in their own minds? Not but for just ends and for a term appointed, did Allah create the heavens and the earth, and all between them: yet are there truly many among men who deny the meeting with their Lord (at the Resurrection)!) (Ar-Rum 30: 2-8)
The Plan for Migrating to Madinah
The most telling example about the importance of planning is shown in the Prophet’s migration from Makkah to Medina. This migration harmoniously coupled systemized planning with placing entire confidence in Almighty Allah.
the Prophet (peace and blessings be upon him) prepared for that migration everything within his capability as a human being, and he took all necessary precautions required in that regard.
he (peace and blessings be upon him) secured the place he would migrate to. He (peace and blessings be upon him) had held two pledges with the people of Madinah, according to which they were to protect him and the Muslims who would migrate to Madinah as they would protect themselves and their own families.
Then, he (peace and blessings be upon him) chose a trustworthy companion, Abu Bakr (may Allah be pleased with him), to accompany him on the trip to Madinah. And Abu Bakr was, no doubt, up to the choice.
He (peace and blessings be upon him) also chose a trustworthy person, `Ali ibn Abi Talib, to sleep in his bed to trick the polytheists who kept vigil all night long, waiting to fall upon him the moment he left his house. They kept peeping every now and then through a hole in the door to make sure the Prophet (peace and blessings be upon him) was still lying on his bed. `Ali (may Allah be pleased with him) accepted the task with great courage and fortitude, though it exposed his life to danger.
he (peace and blessings be upon him) also prepared for a knowledgeable guide, `Abdullah ibn Urayqit, to lead him and Abu Bakr to Madinah. Although that guide was polytheist, he was honest. (In fact, the jurists have derived from this incident that Muslims may seek non-Muslims’ help in worldly domains so long as those people are trustworthy.)
Also, the Prophet (peace and blessings be upon him) chose a neglected cave, Thawr, to hide in for a few days until the polytheists decreased their pursuit. Furthermore, he (peace and blessings be upon him) chose the cave in the opposite direction from Madinah’s in order to mislead the polytheists further.
Moreover, he (peace and blessings be upon him) prepared a team to bring him provision and news during his stay in the cave. The team consisted of Asma’ and `Abdullah, children of Abu Bakr, and `Amir ibn Fuhayrah, a servant of Abu Bakr, who would steal away unobserved every night with a few goats to cover up the tracks of `Abdullah and Asma’.
The above lines show us that the plan he (peace and blessings be upon him) put for migrating to Madinah was a perfect one. He (peace and blessings be upon him) left nothing to chance and assigned every person he chose a certain role to play.
However, even with all these preparations, the plan would have failed when the polytheists reached the mouth of the cave of Thawr and were so close to finding the Prophet (peace and blessings be upon him) and his companion (may Allah be pleased with him). At that point, Abu Bakr, afraid, whispered to the Prophet (peace and blessings be upon him), “Were any one of them to look at the crevice, he would detect us.” The Prophet (peace and blessings be upon him), filled with confidence in Almighty Allah, reassured Abu Bakr: “What do you think, Abu Bakr, of two people supported by (a Mighty) Third?[Have no fear, for Allah is with us) (At-Tawbah 9: 40).
That reply of the Prophet (peace and blessings be upon him) was a clear example of true confidence in Almighty Allah. Through this example, he (peace and blessings be upon him) taught us that one is to do one’s best and take all required precautions on doing things, leaving what is not in one’s capability to Almighty Allah to decide upon however He Almighty wills. This is the core meaning of putting trust in Almighty Allah.