Explanatory Notes on the Whole Bible, by John Wesley, [1754-65], at sacred-texts.com
  
Psalms 130:3
 
psa 130:3
Mark - Observe them accurately and punish them as they deserve. Stand - At thy tribunal. 
Psalms 130:4
 
psa 130:4
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. 
Psalms 130:5
 
psa 130:5
I wait - That he would pardon my sins. 
Psalms 130:6
 
psa 130:6
They - Whether soldiers that keep the night - watches in an army, or the priests or Levites who did so in the temple. 
Psalms 130:7
 
psa 130:7
Israel - Every true Israelite. Plenteous - Abundantly sufficient for all persons who accept it upon God's terms.