Why did Avraham return to the same spot where he had stood the day before?
Rashi (in Bo, 14:10: In order to Daven. 1
Seforno: He wanted to continue where he had left off yesterday - to plead for mercy, although he was unable to find any merits on their behalf according to the Din.
Michtav me'Eliyahu (5 p.427): He fixed a place for his prayer, and made himself a place for revelation of Kevod Hashem, so Hashem became his place.
Intimating that one should fix a permanent place to Daven. Se also Targum Onkelos and Targum Yonasan.