Rashi on Genesis 28:22/רש"י על בראשית כ״ח:כ״ב

1והאבן הזאת THEN THIS STONE — This is how you should explain the ו of והאבן: if He will do these things mentioned in Genesis 28:15 as He promised, then I, also, will do this:

2והאבן הזאת אשר שמתי מצבה THEN THIS STONE WHICH I HAVE SET UP FOR A PILLAR etc. — Explain it as the Targum translates it: “I shall serve the Lord upon it” This, indeed, he did on his return from Padan-aram, when God said to him, (Genesis 35:1) “Arise, go up to Bethel”. What is stated there? “And Jacob set up a pillar … and he poured out a drink-offering thereon” (Genesis 35:14).