9 “The ungodly walk in a circle round about”: that is, in the desire of things temporal, which revolves as a wheel in a repeated circle of seven days; and therefore they do not arrive at the eighth, that is, at eternity, for which this Psalm is entitled. So too it is said by Solomon, “For the wise king is the winnower of the ungodly, and he brings on them the wheel of the wicked.— After Your height You have multiplied the sons of men.” For there is in temporal things too a multiplication, which turns away from the unity of God. Hence “the corruptible body weighs down the soul, and the earthy tabernacle presses down the mind that muses upon many things.” But the righteous are multiplied “after the height of God,” when “they shall go from strength to strength.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)