NEITHER SHALT THOU SET THEE UP A PILLAR — "a pillar of one stone, even for the purpose of sacrificing to Heaven upon it. WHICH THE ETERNAL THY G-D HATETH. An altar of earth¹ and an altar of stones² has He commanded you to make, but He hates this [one-stone pillar] because it was an ordinance of the Canaanites [for idol-worship]. Although it was pleasing to Him at the time of the patriarchs,⁠³ He hates it now, because these [Canaanites] have made it an ordinance in the worship of the idols.⁠" This is Rashi's language. If so, Scripture prohibited [the planting of] an asheirah [anywhere], it enjoined against planting [trees] on the Temple mount although the intent be to Heaven, and it prohibited a pillar [erected] for Heaven — both [prohibitions, against trees and against pillars,] on account of the ordinances of the Canaanites. But I have not understood this ordinance, for the Canaanites used altars as well as pillars since Scripture states, And ye shall break down their altars, and dash in pieces their pillars;⁴ for ye shall break down their altars, and dash in pieces their pillars⁵ and similarly in all places; [hence all altars should have been prohibited even for the worship of G-d]! Perhaps we may say that the Canaanites were primarily devoted to pillars, and they had no idolatrous temple without a pillar upon which to sacrifice and pour oil upon its top,⁠⁶ similar to what is stated with reference to Baal, And they brought forth the pillars that were in the house of Baal.⁠⁷ However, only a few of their temples also had altars upon which to sacrifice [hence Scripture did not prohibit altars built to be used for Heaven].
It appears to me that the Canaanites, who were engrossed in idolatry, used to make in all temples of their gods an altar on which to bring sacrifices, erected a large stone at the entrance of the temple for the priests to stand upon, and planted a tree outside it to point the way for those who come there. They still do so to this day. Now the Glorious Name⁸ hates and despises all their deeds and He prohibited the pillar and the asheirah. He left only the altar because it is a necessity for the offerings concerning which He commanded. They were a source of pleasure before Him — because He ordained them and His Will was done — even prior to the existence of idol-worship on earth.⁠⁹

WHICH THE ETERNAL THY G-D HATETH. The purport thereof is that he is explaining that G-d had commanded, an altar of earth shalt thou make unto Me,⁠¹⁰ And if thou make Me an altar of stones,⁠¹¹ and so, Moses explained, He desires these [altars] excluding the pillar. He hates it because, all their deeds being detestable before Him, He commanded Israel not to copy their deeds. In the days of Jacob, however, the prohibition Neither shall ye walk in their statutes¹² had not yet been ordained and he, therefore, used the pillar in worshipping G-d¹³ as was the custom of those who worshipped [the True G-d in the days of Jacob]. This commandment is thus understood as proceeding from the verse, And if thou make Me an altar of stones.⁠¹⁴ But what He said in the Torah, Neither shall ye erect a graven image, or a pillar¹⁵ refers to a graven image and a pillar in order to place the graven image upon the pedestal for idol-worship, for there Scripture is speaking of idol-worship. He says [there], however, Neither shall ye place any figured stone in your Land to bow down unto it¹⁶ — even to Heaven, because he would appear to worship the mosaics themselves, for the same reason that an asheirah [is prohibited], because it is among the [idolatrous] statutes of the peoples.
Know that an altar is a high structure of stones having four horns, a base, and a circuit above its base, and offerings are burnt between its horns. A pillar is a single large stone which they raise up upon which to burn [incense] or bring offerings, or for the priests to stand upon. A bamah (a high place) is like a mountain — they make it of assembled earth and, upon it, an altar is built upon which to sacrifice. Everything which is lofty and high is so named: I will ascend above 'bamathei' (the heights of) the clouds;¹⁷ upon 'bamathei' (the high places of) the earth.⁠¹⁸ The back of a human being is also called bamah, as it is said, upon 'bamatheimo' thou shalt tread.⁠¹⁹ Similarly Scripture states, And the king [Solomon] went to Gibeon to sacrifice there; for that was the great 'bamah' (high place); a thousand burnt-offerings did Solomon offer upon that altar.⁠²⁰