Is it correct to say that a Companion's interpretation is his own opinion and not something he took from the Prophet (peace and blessings be upon him)?

Question:
The questioner asks: Is it true that the default position regarding a Companion's interpretation is that it is his own opinion, because if it had been from the saying of the Prophet (peace and blessings be upon him), the Companion would have informed us of it?

Answer:
This is an invalid statement. The exegetes have unanimously agreed that a Companion's interpretation is acted upon, because he studied under the Messenger (peace and blessings be upon him) and took the interpretation of the Qur'an from him.