The light of the righteous rejoiceth - They shall have that measure of prosperity which shall be best for them; but the wicked, howsoever prosperous for a time, shall be brought into desolation. Light and lamp in both cases may signify posterity. The righteous shall have a joyous posterity; but that of the wicked shall be cut off. So 1 Kings 11:36; : "And unto his son will I give one tribe, that David my servant may have a light (נר ner, a lamp) always before me." 1 Kings 15:4; : "Nevertheless for David's sake did the Lord give them a lamp, to set up his son after him." See also Psalm 132:17, and several other places.
Very beautiful in its poetry is the idea of the light “rejoicing” in its brightness (compare Psalm 19:5; Job 38:7). Note also the distinction between the “light” and the “lamp.” The righteous ones have the true light in them. That which belongs to the wicked is only derived and temporary, and even that shall be extinguished before long. Compare a like distinction in John 1:8; John 5:35.