Charles H. Spurgeon on Psalms 38:3

neither is there any rest in my bones because of my sin. A Christian in this life is like quicksilver, which hath a principle of motion in itself, but not of rest: we are never quiet, but as the ball upon the racket, or the ship upon the waves. As long as we have sin, this is like quicksilver: a child of God is full of motion and disquiet...We are here in a perpetual hurry, in a constant fluctuation; our life is like the tide; sometimes ebbing, sometimes flowing; here is no rest; and the reason is because we are out of centre. Everything is in motion till it comes at the centre; Christ is the centre of the soul; the needle of the compass trembles till it comes to the North Pole. Thomas Watson.