Sunan Ibn Majah, Chapter: The Chapters on Divorce

a man's father or mother - Shubah (one of the namators) was not sure - ordered him to divorce his wife, and he made a vow that he would free one hundred slaves if he did that. He came to Abu Darda while he was praying the Duha, and he was making his prayer lengthy, and he prayed between Zuhr and 'Asr. Then he asked him and Abu Darda said: "Fulfill your vow and honor your parents." Abu Ad-Darda said: "I heard the Messenger of Allah (saw) say: '(Honoring) one's father may lead one to enter through the best of the gates of Paradise; so take care of your parents, (it is so, whether you take care of them) or not. "