Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: I was at the home of my maternal aunt Sayyidah Maymunah (may Allah be pleased with her). When the Prophet (peace and blessings be upon him) had prayed Isha, he came to her, and it was her night (in turn). He (peace and blessings be upon him) prayed two rak'ahs, then turned and said: "Has the boy gone to sleep?" while I was listening. Then he (peace and blessings be upon him) said in his prayer: "O Allah, place light in my heart, light in my hearing, light in my sight and light in my tongue, and grant me light."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12418