Verse 8 of Psalm 110 is a high point of the psalm, offering us hope:
Redemptiónem misit pópulo suo: mandávit in ætérnum testaméntum suum.
He has sent redemption to his people: he has commanded his covenant for ever.
Redemptiónem (Redemption, deliverance) misit (he has sent) pópulo (to the people) suo (his)
The key words in it are:
redemptio onis f a buying back, ransoming, deliverance, redemption
mitto, misi, missum, ere 3, to send
populus, i, people; the chosen people
This is one of those phrases with a double meaning: it refers firstly to the Old Testament liberation of the Jews from Egypt, and their being given the earthly Jerusalem. But it also of course refers to the coming of Jesus and the promise of the heavenly Jerusalem, as Luke 1:68 makes clear: "Blessed be the Lord God of Israel, for he has visited and redeemed his people.
mandávit (he has commanded) in ætérnum (in eternity, forever) testaméntum suum (His covenant)
The key words are:
mando, avi, atum, are to enjoin, order, command
aeternus, a, um eternal. forever
testamentum, i, n. a covenant, testament
This verse is the climax of the psalm, the making of the new covenant, which unlike the Old, lasts forever as St Robert Bellarmine explains:
Now, Christ redeemed his people from the captivity and the slavery of sin and from the powers of darkness, by the price of his blood, and in such manner he really and truly "hath commanded his covenant forever;" that is, he ordered and settled it finally, that his covenant or his compact regarding true, real salvation, and the enjoyment of the kingdom of heaven, should be everlasting, and not like that of the possession of Palestine, which was only temporary, as we know from experience; and therefore, Jer. 31 has, "Behold, the days will come, saith the Lord, and I will make a new covenant with the house of Israel, and with the house of Juda. Not according to the covenant which I made with their fathers, in the day that I took them by the hand to bring them out of the land of Egypt: the covenant which they made void, and I had dominion over them, saith the Lord. But this shall be the covenant that I will make with the house of Israel, after those days, saith the Lord: I will give my law in their bowels, and I will write it in their heart: and I will be their God, and they shall be my people."
We should thank God for the sacrifice of Christ, which reopened the way to heaven for us, and ask for the grace to take up his invitation and live as good Christians.
In this new covenant the law still has a key role, as St John Chrysostom explains:
“Here he refers to the New Testament: since he mentioned precept and Law, which were broken and aroused his wrath, he says, He sent redemption to his people, as he said in person, "I came not to judge the world, but to save the world." When the Law was transgressed, you see, it dealt punishment: "The Law in fact brings wrath; that is, where there is no law, there is no transgression;" and, "All have sinned and fall short of the glory of God, being justified by his grace as a gift." Hence the psalmist spoke that way, The Lord sent redemption to his people. Yet it is not redemption pure and simple: after redemption there is law as well, so that we may give evidence of a way of life that is worthy of grace."
And you can find the next part of the series here.