It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that he placed water for ablution for the Prophet (peace and blessings be upon him) at the home of his maternal aunt Sayyidah Maymunah (may Allah be pleased with her). When he (peace and blessings be upon him) came out, he asked: "Who placed the water for my ablution?" Sayyidah Maymunah (may Allah be pleased with her) said: O Messenger of Allah, my sister's son. He (peace and blessings be upon him) said: "O Allah, grant him understanding of the religion and teach him interpretation (ta'wil, the exegesis of the Qur'an)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12453