The speaker in Psalm 69 is a servant of God. Even though this psalm contains several prophetic references to the ministry of Jesus according to the Apostle John (69:4 in John 15:25; 69:9 in John 2:17; 69:21 in John 19:29), it is still the voice of David who prays in 69:5-6.

In the midst of his struggles and trials David confesses his “folly” to God and admits that his sins remain in full view of God, even though they may be hidden from the general public. David’s prayer is that the people who trust God and those who seek God not be discouraged or disillusioned as a result of David’s foolishness and failures. David is asking God for assistance and deliverance in the midst of his failure so that the people who look to David and his faith as an example may be encouraged and continue in hope. David fears that if God turns his back on him the faithful followers of God may not understand and may become disillusioned. David admits his own behavior has not helped his situation, but he still asks God to demonstrate his faithfulness so that others who may not know the whole story will continue to walk with God.

Also, one of David’s considerations is the fact that the critics who come against God and against those who have faith in God will gladly use David’s personal failures and political disasters to mock the believing community who trust in God along with David. So, for the sake of the faithful, David asks God to prevent his sins and failures as a man not bring public disgrace on those who claim to trust the name of the God of Israel.

“Fundamentally, Christianity had less in common with the other major religions of the day than it did with Judaism. Because most pagan systems were less dogmatic and did not necessarily conflict with the claims of Jesus in principle, the nature of the clash between Christianity and pagan religion was different. Judaism was perfectly willing to admit, in principle, that the Messiah, who was to come in history, could come ‘under Pontius Pilate.’ It simply could not admit that that particular man, Jesus, in fact was the Messiah. Paganism readily accepted the idea of a Mediator, and could see human beings fulfilling such a role, but it had difficulty attributing so cosmic a task to a single man, or conceiving that it could have been carried out, once for all, in a particular historical setting, ‘under Pontius Pilate.’ ”
("Heresies: Heresy and Orthodoxy in the History
of the Church"
by Harold O.J. Brown)