Fasting during the month of Ramadan is one of the five pillars of Islam which is of paramount significance. The Prophet (peace and blessings be upon him) said, “Islam is built upon five pillars: testifying that there is no god except Allah and that Muhammad is the Messenger of Allah, performing Prayer, paying the zakah, making the pilgrimage to the Sacred House (Hajj), and fasting the month of Ramadan.” (Reported by Al-Bukhari and Muslim). Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
“Generally speaking, most of the scholars and jurists are of the opinion that whoever has neglected or failed to fast for some reason or another is obligated to make up for it if he or she can unless one is terminally ill or advanced in age and therefore unable to do so. If the fasts you have missed are not too many and you are able to make up for them, then you should try your best to make up for them.
There is however another view on this issue. This is a view held by Imam Ibn Taymiyyah. According to him a person who had been away from Islam and now is repentant of his past sins and looks forward to leading a responsible Islamic life is not obligated to make up for the Prayers or fasts he or she has missed or neglected to do in the past. Rather, it is enough for him or her to repent and ask Allah for forgiveness repeatedly. His reasoning is that to insist that they should make up for their Prayers and fasts would only serve as a deterrent against their repentance; in other words, it would not encourage them to come forward and repent. Ibn Taymiyyah says that since the main thrust of the Qur’an and the Sunnah is to give hope for the sinners and give them glad tidings so that they wholeheartedly embrace the path of repentance, such a ruling is closer to the spirit of these laws. I think this view of Ibn Taymiyyah is founded on a sound understanding of the wisdom and purposes of the Shari`ah laws.
So if you find yourself burdened by these fasts you have missed in the past, you may follow the view of Imam Ibn Taymiyyah. If, however, you find it easy to do them, then go ahead and do them. The Prophet (peace and blessings be upon him) reassured us saying, ‘This religion of ours is simple and easy to comply with; so whoever makes it hard will only be defeated by it.’”