en_tn/isa/57/07.md

Yahweh continues speaking to the unfaithful people of Israel.

on a high mountain

People often went on top of hills and mountains to worship false gods. They thought those were the best places for worship. This might even refer to Jerusalem, too. (See: rc://en/ta/man/translate/figs-explicit)

you prepared your bed

This refers to having sex with prostitutes as a part of worshiping false gods. (See: rc://en/ta/man/translate/figs-euphemism)

You made a covenant with them

AT: "You made a contract with them" or "You bribed them"

made yourselves naked, and went up; you made your bed wide. You made a covenant with them; you loved their beds; you saw their private parts

This refers to the Israelites joining with those who worship false gods. This also included participating in sexual immorality.