"And when God took a covenant from those who were given the Book, [saying]: You shall surely make it clear to the people," to the end of the verse. This is a covenant that God took from the scholars of the People of the Book: that they must explain to the people what is in their Book, which includes the [prophecy of the] Messenger of God and Islam. "But they cast it behind their backs and purchased with it a small price," meaning what they used to obtain of worldly gain in return for it. "And wretched is what they purchased," they purchased the Fire in exchange for Paradise.