וַיַּשְׁכֵּ֨ם יַעֲקֹ֜ב בַּבֹּ֗קֶר וַיִּקַּ֤ח אֶת־הָאֶ֙בֶן֙ אֲשֶׁר־שָׂ֣ם מְרַֽאֲשֹׁתָ֔יו וַיָּ֥שֶׂם אֹתָ֖הּ מַצֵּבָ֑ה וַיִּצֹ֥ק שֶׁ֖מֶן עַל־רֹאשָֽׁהּ׃
Keesokan harinya Yakub bangun pagi-pagi, lalu ia mengambil batu yang tadi diletakkannya di sekitar kepalanya, mendirikannya sebagai tugu, dan menuangkan minyak di atasnya.
Chizkuni
ויקח את האבן, “he took the stone;” according to the sages in Pirkey de rabbi Eliezer, chapter 35, this stone was the one known in later generations as the even shetiyah’ symbolising the navel of the globe a mystical stone at the site where the Holy Ark had stood in the Holy of Holies during the first Temple. This stone, if removed, would expose a hole going down to the center of the earth. It is supposed to have served G-d as the first piece of solid material of what would be the globe on which we live.
Ramban
AND HE SET IT UP FOR A PILLAR. Our Rabbis have explained52Yerushalmi Abodah Zarah IV, 5. the difference between a pillar and an altar by saying that a pillar consists of one stone while an altar is composed of many stones. It further appears that a pillar is made for pouring libations of wine upon it and for the pouring of oil upon it, but not for sacrifices and not for offerings, whereas an altar is for bringing Burnt-offerings and Peace-offerings thereon. When Israel entered the Land, the pillar was prohibited to them53Deuteromony 16:22. because the Canaanites had established it as an ordinance of an idolatrous character to a greater extent than the altars. Even though it is written concerning the altars, Ye shall break down their altars,54Exodus 34:13. [since the altars were not as prevalent as pillars among the Canaanites, He did not prohibit the Israelites from making their own altars]. It may be that He did not want to prohibit all sacrifices, and so He retained the altar as fit for libations and sacrifices.
Rashbam
ויצק שמו על ראשה, he anointed it to sanctify it and to make it ready to offer sacrifices on it when he would return to that site. We have such formulations in connection with the sanctification of the various materials donated for the Tabernacle (Numbers 7,1) as well as in Genesis 31,13 and again in verse 22 in our chapter here.