The primary reference for this song, especially the refrain, is found in Romans 3:9-24.
The reference in stanza 3 about God’s action of looking down and searching for goodness is also found in II Chronicles 16:9.
This song speaks about the fall into sin and the resulting sinfulness of the human race. God’s people are called to be aware of the fall. Belgic Confession, Article 14 summarizes the fall and its impact with these words: “They subjected themselves willingly to sin and consequently to death and the curse...”
Heidelberg Catechism, Lord’s Day 3, Question and Answer 7 points out that “this fall has so poisoned our nature that we are all conceived and born in a sinful condition.” Yet, God’s people are also called to know about God’s grace, which is freely given, despite the depravity of the world. Our World Belongs to God, paragraph 14 claims that “we prove each day apart from grace that we are guilty sinners...”