If thou, LORD, shouldest mark iniquities, O Lord, who shall stand?
Mark — Observe them accurately and punish them as they deserve.
Stand — At thy tribunal.

But there is forgiveness with thee, that thou mayest be feared.
Forgiveness — Thou art able and ready to forgive repenting sinners.
Feared — Not with a slavish, but with a childlike fear. This mercy of thine is the foundation of all religion, without which men would desperately proceed in their impious courses.

I wait for the LORD, my soul doth wait, and in his word do I hope.
I wait — That he would pardon my sins.

My soul waiteth for the Lord more than they that watch for the morning: I say, more than they that watch for the morning.
They — Whether soldiers that keep the night-watches in an army, or the priests or Levites who did so in the temple.

Let Israel hope in the LORD: for with the LORD there is mercy, and with him is plenteous redemption.
Israel — Every true Israelite.
Plenteous — Abundantly sufficient for all persons who accept it upon God's terms.