Psalm 55:22 says, "Cast your burden upon the LORD and He will sustain you;
He will never allow the righteous to be shaken." What does "to be shaken" mean?

From John Gill's Commentary

"and he shall sustain thee; in being, both natural and spiritual; and supply with all things necessary both to the temporal and spiritual life, and support under all trials and difficulties;he shall never suffer the righteous to be moved; to be shaken and stagger so as to fall, especially totally and finally; for the words may be rendered, “he shall never suffer the righteous to be moved for ever”; or so to be moved by their afflictions as to desert the cause in which they are engaged; nor shall they ever be moved by men or devils, or anything whatever, from their spiritual estate, in which they are by grace; nor from the love of God and covenant of grace; nor out of the hands of Christ; nor from their state of justification, adoption, and sanctification."