'Covenant and Mercy' in the Bible

And said, I beseech thee, O LORD God of heaven, the great and terrible God, that keepeth covenant and mercy for them that love him and observe his commandments:

Now therefore, our God, the great, the mighty, and the terrible God, who keepest covenant and mercy, let not all the trouble seem little before thee, that hath come upon us, on our kings, on our princes, and on our priests, and on our prophets, and on our fathers, and on all thy people, since the time of the kings of Assyria unto this day.