Note: This psalm is classified as an individual lament. The situation that inspired these words is not known, although some suggest it may have been illness.
For the director of music. A psalm of David.
A. Expression of Despair
13:1 [note the fourfold repetition of “How long?”]  How long [the repetition of these words expresses the intensity or depth of emotions], Lord? Will you forget me forever [or “continually”]?  How long will you hide your face from me [an expression for alienation; suffering is intensified when we feel we are all alone]?
13:2  How long must I wrestle with my thoughts [the psalmist is struggling to determine what has happened to cause his suffering; “wrestle with my thoughts” may also connote worry] and day after day [every day or day and night] have sorrow in my heart?  How long will my enemy [no indication of who the enemy is (perhaps death, unidentified oppressors, evil)] triumph over me [the smallest troubles seem huge when we feel that the Lord has forgotten us]?
B. Expression of Prayer
13:3 [note the threefold prayer] [A] Look [an indication of favor] on me [because he feels that God has hidden His face from him (cf. vs. 1)] and [B] answer [an indication of favor], Lord my God. [C] Give light to my eyes [our countenance reveals our inner spiritual condition], or I will sleep in death [may refer to a state of depression or suffering],
13:4 and my enemy [either adversaries or adversities] will say, “I have overcome him,” and my foes will rejoice [because of his fall and because of God’s failure to rescue him] when I fall [severity of troubles or weight of his burden is causing his feet to slip and his knees to buckle].
C. Expression of Hope
13:5 But [this conjunction introduces the difference that trusting God can make when we feel overwhelmed by troubles] I trust [an expression of faith in God; the answer had not arrived but the psalmist believed that it was on its way] in your unfailing love [Hebrew: ḥeseḏ]; my heart rejoices in your salvation.
13:6 I will sing the Lord’s praise [an appropriate expression of gratitude; “David’s heart was more often out of tune than his harp. He begins many of his psalms sighing, and ends them singing.” (Spurgeon)], for he has been good to me.