Psalm 51 is classified as a lament, and is the most famous of the seven penitential psalms (6, 32, 38, 51, 102, 130, 143) . This psalm deals with the reality of sin and how only the Grace of God can wash away sin and that one must be penitent to ask God make one’s self whiter than snow.
Psalm 51 is also so important in the official prayer of the Catholic Church (The Liturgy of the Hours) that it is prayed in Morning Prayer (Lauds) on Friday mornings of all four weeks of the ordinary cycle. This psalm is also included in the Morning prayer in the Office for the Dead.
A deep reflection on the verses of this psalm reveal a special connection to the Holy Spirit. The psalmist asks for the following: wisdom and joy. Also the psalmist will “teach the wicked”, to teach would require knowledge and counsel, and since the wicked would not learn willingly, also fortitude. These are the fruits and gifts of the Holy Spirit. The Psalmist (inspired to write this by the same Holy Spirit), knows these gifts will only come when sin has been acknowledged, confessed and cleansed by God. It is only then, when sin has been removed by God, can one truly proclaim the praise of God.