Note: This psalm is a parallel version of Psalm 14.
For the director of music. According to mahalath [probably a musical term]. A maskil [probably a literary or musical term] of David.
53:1 The fool [term synonymous with “wicked” and refers to one who is morally deficient; not necessarily someone who is ignorant or an atheist but instead one who disregards and tries to live independently from God; one who does not feel accountable to God for his behavior (cf. Ps. 10:3-11)] says in his heart [indication that the “fool” has convictions; “On earth are atheists many, In hell there are not any.” (T. Brooks)], “There is no God [denies the importance of God’s existence].” They [the wicked or fools] are  corrupt [actions or behavior that is ruinous], and their ways [or deeds] are vile [acts done with complete disregard for God and His expectations]; there is  no one who does good [summary statement; the sum of a life lived without regard for God].
53:2 God looks down [to witness and observe our actions; everything we do is in the sight of the Lord; we can never do anything behind God’s back] from heaven on all mankind to see if there are any [God is looking for those who are wise…] who understand [the wise understand and act according to their understanding of God’s revelation of Himself], any who seek [and live according to God’s standards] God.
53:3 [what God sees when He looks down…]  Everyone has turned away [to become apostate],  all have become corrupt [meaning derived from Arabic, “to make sour” (as of milk)];  there is no one [reinforces the previous use of the word “all” to define the scope of the problem] who does good, not even one.
53:4 Do all these evildoers know nothing? They devour [as they pursue their selfish interests; they do so with complete disregard for the rights of others; they have an insatiable appetite] my people [and their possessions] as though eating bread; they never call on the Lord [the evildoers do not care that God is looking down from heaven or will one day call them to account for their actions].
53:5 But [the day of reckoning will come] there they are, overwhelmed with dread, where there was nothing to dread. God scattered the bones of those who attacked you; you put them to shame, for God despised them.
53:6 [a prayer for the salvation of God’s people, possibly at a time of national disaster like the Exile] Oh, that salvation for Israel would come [the day when God will save His people from those who oppress them] out of Zion! When God restores his people, let Jacob rejoice [because of God’s saving acts on their behalf] and Israel be glad!