1 Nephi 14:10; “And he said unto me: Behold there are save two churches only; the one is the church of the Lamb of God, and the other is the church of the devil; wherefore, whoso belongeth not to the church of the Lamb of God belongeth to that great church, which is the mother of abominations; and she is the whore of all the earth.”

Jeremiah 3:6; “The LORD said also unto me in the days of Josiah the king, Hast thou seen that which backsliding Israel hath done? she is gone up upon every high mountain and under every green tree, and there hath played the harlot.”

The passages in Jeremiah are one place Smith might have picked up the phrase “the whore of Babylon”.  Many times the Lord tried to call her back but Judah was too busy worshipping other gods to pay attention to the one true God.