The hymn is sung to the tune "Aus tiefer Not." Here's the first musical phrase:
The first line is "From depths of woe I cry to Thee." As if to reflect those "depths," that word is sung to the lowest pitch in the phrase (and in the entire hymn).
The same musical phrase is repeated as the third phrase, and in the first verse, the text there is "Bend down Thy gracious ear to me." Here, the initial falling fifth (B to E) illustrates that "Bend[ing] down."
Here's the second musical phrase:
In the fifth verse, the text here is "Is God's abundant favor" (it completes the sense from the previous line: "Though great our sins, yet greater still"). "Favor" is sung with a melisma (G F E), giving a sense of amount (for "abundant").
The same musical phrase is also repeated as the fourth phrase, and in the fifth verse, the text there is "Abandon us, nor waver" (again, this completes the sense from the previous line: "His hand of mercy never will"). "Waver" is sung with the same melisma (G F E), so while it's negated, there's a sense of the word's meaning.