My friend, this is who you are called to be above all else: waiting upon God, through putting yourself deliberately before the Lord; and knowing God as he is in his steadfast love and mercy, in his sovereign kindness and goodness, and in his urgent and relentless desire to reveal himself to you in blessing. This is life and hope and joy.
The psalmist ( David in this case) starts out describing God as “his fortress” and says “I shall not be greatly moved.” In other words, things and circumstances may come against me, and they may rock me a bit “but I shall not greatly be moved”.
But see what happens next. Again he waits upon the Lord in silence ( verse 5), and again he testifies to the Lord being his defender - but now he says “ I shall not be shaken”. Not even as a leaf trembling in the wind - he has made himself secure by resting in him who is The Rock.
We are foolish when we don’t wait upon the Lord in prayer and reading his word. We forsake the grace that could be ours.