Hebrews 12:15

Deuteronomy 29:18 NIV
Make sure there is no man or woman, clan or tribe among you today whose heart turns away from the Lord our God to go and worship the gods of those nations; make sure there is no root among you that produces such bitter poison.

Galatians 5:4 NIV
You who are trying to be justified by the law have been alienated from Christ; you have fallen away from grace.

Hebrews 3:12 NIV
See to it, brothers and sisters, that none of you has a sinful, unbelieving heart that turns away from the living God.