Seeing as the angel instructed Hagar to call her son by the name Yishmael, how come that it was Avraham who now names him?
Refer to 16:11:1.
QUESTIONS ON RASHI
Rashi writes: "Avraham was inspired by Ru'ach ha'Kodesh, and named him Yishma'el." But perhaps he heard from Hagar that Hashem had commanded to name him this?
Gur Aryeh: If so, why does the verse specify that Avraham named him Yishma'el? 1 Rather, Avraham himself was told to do so by Hashem at this point.
In many instances in Sefer Bereishis, the Torah attributes the naming of the child to the mother rather than the father (e.g. Kayin (Bereishis 4:1); as well as all of the Shevatim other than Levi and Binyamin). Here as well, the naming could have been attributed to Hagar. (CS)