Islam urges Muslims to have good human relationships with all people. When it comes to one’s relationship with the employers or the bosses, Islam strongly recommends Muslims to be on friendly terms with them but there should be neither flattering nor lip service, especially when one does that to get a promotion that he/she doesn’t deserve.
Dr. Rif`at Fawzi, former professor of Shari`ah at Cairo University, states the following: “The relationship between Muslims should be based on truth and sincerity. There is nothing wrong in Islam with a Muslim praising his fellow Muslim as long as there is no hidden purpose that might jeopardize others or cause them harm. When a Muslim praises others, he should do it solely for Allah’s sake and not for the purpose of adulation and lip service. The word uttered should be a true reflection of what is inside!
The true Muslim is the one who always keeps himself aloof of nifaq (hypocrisy) and all its signs so as to gain Allah’s reward in this life and in the Hereafter. The Prophet (peace and blessings be upon him) is reported to have said: “The hypocrite has three characteristics: he tells lies, breaks his promise, and breaches the trust.” (Al-Bukhari and Muslim)
Based on the above, I can say that it is unlawful for a Muslim to utter untrue words to please his or her employer in order to get a promotion at work or to get a better job.”