Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: I used to pass by this verse and not know what it meant, namely the saying of Allah Almighty: "In the evening and at sunrise (ishraq)" [Sad: 18], until Umm Hani bint Abi Talib (may Allah be pleased with her) told me that the Messenger of Allah (peace and blessings be upon him) came to her and called for water for ablution in a large bowl; it is as if I can see the traces of dough in it. He (peace and blessings be upon him) performed ablution, then stood and prayed the Duha prayer, and said: "O Umm Hani! This is the prayer of Ishraq."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21354