"God has been so good to us!

We were idolaters, and if the Messenger of God had come with this entire religion all at once, and with the Quran all at once, the responsibilities would have weighed heavily upon us, and we would not have entered Islam. Rather, he called us to a single word, and when we accepted it and tasted the sweetness of faith, we accepted what came after it, word upon word, in a gentle way, until the religion was completed and the law was perfected.

-Imām 'Alī, quoted in The Study Qur'an, p. 174, commentary on Q3:159.