Psalms 106:38
And shed innocent blood, even the blood of their sons and of their daughters, whom they sacrificed unto the idols of Canaan: and the land was polluted with blood. And shed innocent blood, even the blood of their sons and of their daughters, whom they sacrificed unto the idols of Canaan: and the land was polluted with blood.
Israel shed innocent blood by sacrificing their own sons and daughters to the idols of Canaan, and that bloodshed polluted the land. This child sacrifice came after Israel mingled with the surrounding nations, learned their practices, and served their idols. It was part of turning from God's ways and adopting heathen practices, including human sacrifice. The next verse reveals that these idol sacrifices were actually made to demons, so that what appeared to be worship of the dead was really worship of demons.
This bloodshed was part of Israel's unfaithfulness that provoked the Lord's anger against His people. This disobedience in Canaan brought God's judgment upon Israel in the form of oppression. As part of Israel's recorded experience, the verse provides warning lessons that God's people in the last days need to study.
As part of Israel's history, it warns God's people in the last days not to turn to idolatry. As part of Psalms 103 through 107 repeated by a large and growing multitude passing one by one through a very narrow gate that admits no burden, its testimony about sacrificing to Canaan's idols shows that entering requires relinquishing idols, and those unwilling to give them up are left behind. The offerings associated with the Moabites and Amorites illustrate the verse's polluted land, picturing a polluted offering to God, which is a sin-stained soul.