Prophet Abraham asking Allah to accept their repentance upon completing the House of Allah

> Our Lord, and make us Muslims [in submission] to You and from our > descendants a Muslim nation [in submission] to You. And show us our > rites and accept our repentance. Indeed, You are the Accepting of > repentance, the Merciful. —Baqarah 2:128 Do we know *exactly why* Prophet Abraham is asking Allah to accept their repentance? (Obviously, one can repent anytime, on any occasion, but Allah must have a reason to narrate us this specific occasion; and it is not that Prophet Abraham and and his son Ishmael did something bad; on the contrary, they have just completed the House of Allah.)