Is knowledge to be taken from one who disagrees on some issues?

Question:
Honorable Shaykh, may Allah grant you success, you mentioned (may Allah preserve you) that Abu al-Ma'ali al-Juwayni has truth with him, and he has some of the statements of the theologians (mutakallimun). Does that mean that knowledge is to be taken from a person even if he has some falsehood?

Answer:
The truth is taken from the one who brought it; the truth is taken from the one who brought it, and the falsehood is rejected from the one who brought it. Satan said to Abu Dharr, "I will teach you a verse." When he seized him, he was scattering dates. It was mentioned that he was the head of a family and that he was poor, so he released him. When he came to the Messenger (peace and blessings be upon him) in the morning, he said, "What did your captive do last night?" He said, "He promised that he would not come again." He said, "He told you the truth, and he is a liar. He told you the truth when he said to him, 'I will teach you a verse; if you recite it, I will never come again.' That is the Verse of the Throne. He told you the truth that the Verse of the Throne prevents Satan, but he is a liar in matters other than this. So the truthful liar may tell the truth some of the time. For this reason, the common people say, "What a truth the liar spoke today." Yes.