What is the ruling on appeasing disbelievers at the expense of certain unalterable tenets of faith — such as the disbelief of Christians — when there is a necessity, and was the Prophet's weeping over his uncle upon his death out of love for him?

The disbelief of the People of the Book is a known essential tenet of the religion. Whoever denies their disbelief or doubts it commits an act of disbelief (kufr), with the exception of one who is coerced. Flattery (mudāhanah) in this matter is not an excuse; it is forbidden. Mudāhanah means showing satisfaction with the action of a transgressor without denouncing it. This differs from circumspection (mudārāh), which involves gentleness towards the ignorant and the transgressor, while still denouncing their actions kindly. The difference between them is that mudārāh involves expending worldly things for the betterment of religion or worldly affairs, and it is permissible and even recommended. Mudāhanah, on the other hand, involves abandoning religion for the sake of worldly gain, and it is forbidden. The Prophet, peace and blessings be upon him, grieved over the death of his uncle Abu Talib, who died in disbelief, due to his love for him and his keenness for his guidance, and his loss of support and consolation. His love for him was a natural, instinctive affection, not a religious one.