Albert Barnes Commentary Psalms 119:124

"Deal with thy servant according unto thy lovingkindness, And teach me thy statutes." — Psalms 119:124 (ASV)

Deal with thy servant according unto thy mercy - Not according to justice—for, sinners as we are, we can never urge that as a plea before God. No one who knows himself could ask God to deal with him according to the strict and stern principles of justice.

But we may ask Him to deal with us according to mercy—for mercy is our only plea, and the mercy of God—vast and boundless—constitutes such a ground of appeal as we need. No one can have any other; no one need desire any other.

And teach me thy statutes - See the notes at Psalm 119:12. Show your mercy to me in teaching me your law.