Psalms 78:37

For their heart was not right with him
Neither prepared and ready to any good work, but reprobate thereunto; nor steady, fixed, and established, as a good man's heart is, trusting in the Lord; but wavering, fickle, and inconstant; nor true, faithful, and upright; but turning aside like a deceitful bow, as is afterwards said, ( Psalms 78:57 ) ,

neither were they steadfast in his covenant;
which was made with them at Sinai, though they promised to be obedient, and to do all the Lord said unto them; but this covenant they broke, though he were an husband to them; see ( Exodus 24:7 ) ( Jeremiah 31:32 ) .