16:21Meaning
Do not plant an Asherah by Yahweh’s altar Israel is told not to “plant” an Asherah, described as “any kind of tree,” beside the altar made for Yahweh. The instruction is concrete and spatial: even if an altar is built for Yahweh, adding this planted object next to it is prohibited. The altar is assumed to be legitimate (“which you shall make”), but the added tree-symbol is not.
