For their heart was not right with him, neither were they stedfast in his covenant.

For their heart was not firm toward him, neither were they stedfast in his covenant.

For their heart was not right with him, neither were they steadfast in his covenant.

And their hearts were not right with him, and they did not keep their agreement with him.

For their heart was not right with him - Luther renders this, "Not fast with him." The Hebrew word means "to fit, to prepare;" and the idea is, that the heart was not "adjusted" to such a profession, or did not "accord" with such a promise or pledge. It was a mere profession made by the lips, while the heart remained unaffected. See the notes at Psalm 78:8.
Neither were they stedfast in his covenant - In maintaining his covenant, or in adhering to it. Compare Psalm 25:14; Psalm 44:17. See also Psalm 78:8.

Their heart was not right - When the heart is wrong, the life is wrong; and because their heart was not right with God, therefore they were not faithful in his covenant.

For their (u) heart was not right with him, neither were they stedfast in his covenant.
(u) Whatever does not come from the pure fountain of the heart is hypocrisy.

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, Psalm 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.

heart . . . not right--or, "firm" (compare Psalm 78:8; Psalm 51:10).