The Hebrew word Chesed is the magnificent word describing God’s Covenant faithfulness, not unlike grace in the NT. Variously translated by steadfast love (RSV) Lovingkindness (NASB) and here in the NLT as unfailing love. Notice it twice in this beautiful passage. The associated words of ‘faithfulness’, ‘righteousness’ and ‘judgements’ are facets of the covenant word. David has compared these words to the biggest things he knows – the heavens, the skies, the mountains, the great deep, and the shadow of His wings represented by the overarching wings of the angels in the Most Holy Place above the mercy seat – the Ark of the Covenant.

Psalm 36:5-9 (NLT)

5 Your unfailing love, O Lord, is as vast as the heavens;
    your faithfulness reaches beyond the clouds.

6 Your righteousness is like the mighty mountains,
    your justice like the ocean depths.
You care for people and animals alike, O Lord.

7     How precious is your unfailing love, O God!
All humanity finds shelter
    in the shadow of your wings.

8 You feed them from the abundance of your own house,
    letting them drink from your river of delights.

9 For you are the fountain of life,
    the light by which we see.