Why do the Imams differ? And is it permissible to adopt any of their opinions?

The disagreement among the imams is due to some of them not being aware of a text, or believing another text to be more authentic, or differences in understanding, or perceiving a text to be abrogated, or specialized, or restricted. As for one who is capable of knowing the proofs and the stronger opinion, he should follow the stronger opinion. However, for one who is not qualified, it is permissible for him to follow whichever of the imams' opinions is easiest for him.