Keep back Thy servant also from presumptuous sins; let them not have dominion over me: then shall I be upright, and I shall be innocent from the great transgression.
Let the words of my mouth, and the meditation of my heart, be acceptable in thy sight, O LORD, my Strength, and my Redeemer.
David knew his own propensity for sin. He had, after all, been guilty of the seduction of an innocent woman; the murder of her husband, and so much more. Here, he is asking God to keep him from committing any more presumptuous sins.
Presumptouous means arrogant, proud, or insolent. It is thinking more highly of ourselves than we ought to think; assuming that we have ultimate authority over our lives. It is too easy for us to forget that He Who made us is the sovereign, ultimate authority.
The great transgression indicates an ongoing and unrepentant rebellion against God. The word great is translated as numberless; countless.
The final verse of this Psalm is one I’ve committed to memory too long ago to remember exactly when I learned it. In my own words: Let the words that I say, and the thoughts and intentions in my heart, be only those that please You, Lord. You are my Strength. You are the One Who has redeemed me from the gates of hell.
Reviewing this verse reminds me, painfully, of how far I have to go to reach fulfillment of it.