Passage
Who understandeth [his] errors? Purify me from secret [faults].
Who understandeth [his] errors? Purify me from secret [faults].
Psalms 19:10 They are more precious than gold, yea, than much fine gold; and sweeter than honey and the dropping of the honeycomb.
Psalms 19:11 Moreover, by them is thy servant enlightened; in keeping them there is great reward.
Psalms 19:12 Who understandeth [his] errors? Purify me from secret [faults].
Psalms 19:13 Keep back thy servant also from presumptuous [sins]; let them not have dominion over me: then shall I be perfect, and I shall be innocent from great transgression.
Psalms 19:14 Let the words of my mouth and the meditation of my heart be acceptable in thy sight, O Jehovah, my rock, and my redeemer.
The verse centers on "understandeth", "errors", "purify", "secret", and "faults". It is saying that the verse draws attention to "understandeth" and "errors", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 11's "Moreover by them is thy servant enlightened..." into verse 13's "Keep back thy servant also from presumptuous...", so "understandeth" and "errors" belong inside that flow. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "understandeth" and "errors" with trust shaped by these words, not by a vague optimism outside the passage.