Psalm 6 New King James Version (NKJV)
A Prayer of Faith in Time of Distress
To the Chief Musician. With stringed instruments. On [a]an eight-stringed harp. A Psalm of David.
6 O Lord, do not rebuke me in Your anger,
Nor chasten me in Your hot displeasure.
2 Have mercy on me, O Lord, for I am weak;
O Lord, heal me, for my bones are troubled.
3 My soul also is greatly troubled;
But You, O Lord—how long?
4 Return, O Lord, deliver me!
Oh, save me for Your mercies’ sake!
5 For in death there is no remembrance of You;
In the grave who will give You thanks?
6 I am weary with my groaning;
[b]All night I make my bed swim;
I drench my couch with my tears.
7 My eye wastes away because of grief;
It grows old because of all my enemies.
8 Depart from me, all you workers of iniquity;
For the Lord has heard the voice of my weeping.
9 The Lord has heard my supplication;
The Lord will receive my prayer.
10 Let all my enemies be ashamed and greatly troubled;
Let them turn back and be ashamed suddenly.
Psalm 6 is the first of the penitential psalms. What is a penitential psalm? Well, it is a psalm that helps us to express repentance.
feeling or expressing humble or regretful pain or sorrow for sins or offenses : repentant
David, the man who wrote this psalm, was a man beloved of God. He was also a king. Nevertheless, David was like us. David was a sinner. Unlike some, David mourned over his sins.
Here how Spurgeon describes Psalm 6 overall.
DIVISION. You will observe that the Psalm is readily divided into two parts. First, there is the Psalmist’s plea in his great distress, reaching from the first to the end of the seventh verse. Then you have, from the eighth to the end, quite a different theme. The Psalmist has changed his note. He leaves the minor key, and betakes himself to sublimer strains. He tunes his note to the high key of confidence, and declares that God hath heard his prayer, and hath delivered him out of all his troubles. (from here)
How can we use such a psalm? Well, we have the example of Augustine of Hippo. R.C. Sproul, now deceased, described (here in a Renewing Your Mind broadcast) Augustine was one of the most influential theologians who ever lived. Sproul says Augustine spent his final days in bed reading the penitential psalms. Wikipedia’s article includes these details.
Whether we are haunted to wakefulness by a bad dream, rocked by dangerous experience, or lying on our death-bed, death is frightening. Augustine apparently found comfort in the penitential psalms, knowing that if we sincerely repent and ask for forgiveness our Lord is quick to forgive.
The Seven Penitential Psalms and the Songs of the Suffering Servant (usccb.org) provides a Catholic perspective. This article also discusses four poetic sections from the Book of Isaiah known as the Songs of the Suffering Servant.