Psalms 13:5,6

But I have trusted in thy mercy; my heart shall rejoice in thy salvation.

But I have trusted in thy mercy [ checed (H2617 )]; my heart shall rejoice in thy salvation. David's 'rejoicing' in the Lord's salvation, which he anticipates by faith, stands in contrast to the enemy's rejoicing in his anticipated fall.

Because he hath dealt bountifully with me - the Hebrew х gaamal (H1580)] commonly means to requite; here, to deal bountifully with him, making up for his former adversity, as in Psalms 119:17; Psalms 142:7; Zechariah 9:12; Isaiah 40:2. The Septuagint, Vulgate, the Ethiopic versions, and 'the Great English Bible,' (so the Book of Common Prayer), add, 'Yea, I will praise the name of the Lord Most Highest.' The addition is not in the Hebrew, and is probably taken from Psalms 7:1, end.