Exodus 34:14

For thou shalt worship no other god: for the LORD, whose name is Jealous, is a jealous God:

Thou shalt worship no other god: for the Lord, whose name is Jealous, is a jealous god. The first commandment is frequently taken as a test of adherence to the national covenant. While the breach of any precept of the Decalogue was a sin against God, He who knew the inconstancy and fallibility of man did not consider every infringement of the law as implying a violation of the compact between Him and Israel; but obedience to God, as the true and only object of religious worship lying at the basis of the covenant, a transgression in that one fundamental point was tantamount to the guilt of offending in all; and hence, God is never represented as angry or jealous except for a breach of the first, which was the whole law (cf. Deuteronomy 6:14; Deuteronomy 11:16; Deuteronomy 31:29; Deuteronomy 32:21; 'Israel after the Flesh,' p. 18).