Exodus Chapter 23, Verse 21

21: Beware of him, and obey his voice, provoke him not; for he will not pardon your transgressions: for my name is in him.- edit KJV text
21: Take notice of him, and hear his voice, and do not think him one to be contemned: for he will not forgive when thou hast sinned, and my name is in him.— edit Douay text
21: Take heed to thyself and hearken to him, and disobey him not; for he will not give way to thee, for my name is on him.— edit LXX text