Psalm 79:9

Help us, O God of our salvation, for the glory of thy name: and deliver us, and purge away our sins, for thy name's sake.

Help us, O God of our salvation, for the glory of thy name,.... Help us out of the troubles in which we are; enable us to bear them with patience, and without murmuring, while it is thy pleasure to continue them; assist us against our powerful enemies, and strengthen us to do our duty; afford us more grace, and fresh supplies of it in our time of need: the arguments enforcing these petitions are, because God is "the God of salvation", to whom it belongs, of whom it is, and of him only to be expected; he is the sole author and giver of it; and because to help and save is for the glory of his name, which is great in the salvation of his people:

and deliver us; out of the hands of all our enemies, and out of all our afflictions, and out of this low estate in which we are:

and purge away our sins for thy name's sake; which were the cause of all calamities and distress, and which can only be purged away by the blood and sacrifice of Christ, Hebrews 1:3, the word signifies to "expiate" {i} sin, or atone for it; which was the work and business of Christ our High Priest, who has made reconciliation for sin, finished, made an end of it, and put it away by the oblation of himself, for the sake of which God is propitious; and so the words may be rendered, "be propitious to our sins" {k}: or merciful to our unrighteousnesses, for the sake of Christ the great propitiation; or through the propitiatory sacrifice to be offered up by him; or, in other words, "cover our sins" {l}; which is also the sense of the phrase, that they may be seen no more; pardon and forgive them for Christ's sake; see Psalms 32:1.

{i} rpk "expiationem fac", Junius & Tremellius, Piscator, Michaelis.
{k} "Propitiare", Pagninus, Montanus; "propitius esto", V. L. Musculus; so Tigurine version.
{l} rpk metaph. "texit", Amama.