"תַּנְיָא כְּווֹתֵיהּ דְּרַבִּי יוֹסֵי בְּרַבִּי חֲנִינָא:
אַבְרָהָם תִּקֵּן תְּפִלַּת שַׁחֲרִית, שֶׁנֶּאֱמַר: ״וַיַּשְׁכֵּם אַבְרָהָם בַּבֹּקֶר אֶל הַמָּקוֹם אֲשֶׁר עָמַד שָׁם״,
וְאֵין ״עֲמִידָה״ אֶלָּא תְּפִלָּה"
Abraham instituted the morning prayer, as it is stated: “And Abraham rose early in the morning to the place where he had stood before the Lord” (Genesis 19:27), and the verb "standing" means nothing other than prayer,
From the aforementioned verse, it follows that arguing about Sodom's destiny was the moment when Abraham davened as the Targum translate it: "תַּמָּן בִּצְלוֹ קֳדָם יְיָ".
Was it the first time Abraham prayed to God? If not, when did Abraham start to daven the morning prayer and why?