Jamieson, Fausset and Brown on Psalms 56:1-2

PSALM 56

Psa 56:1-13. Upon Jonath-elem-rechokim--literally, "upon the dove of silence" of distant places; either denoting a melody (see on Psa 9:1) of that name, to which this Psalm was to be performed; or it is an enigmatical form of denoting the subject, as given in the history referred to (1Sa 21:11, &c.), David being regarded as an uncomplaining, meek dove, driven from his native home to wander in exile. Beset by domestic and foreign foes, David appeals confidently to God, recites his complaints, and closes with joyful and assured anticipations of God's continued help.

1-2. would swallow--literally, "pants as a raging beast" (Ac 9:1).