The psalm antiphon for Monday Compline in the OF:
|Tu, Dómine Deus, pátiens et multæ misericórdiæ.||You, Lord God, are patient and of much mercy.|
Tu = you. In Latin there are two ways to say this. Vos is plural (you-all) and tu is singular (you).
Dómine Deus = Lord God.
pátiens = patient, from patiens, patientis. In English we would expect some form of the verb to be to precede, as in “You, Lord God, are patient.” So often the case in Latin, the word est is omitted because it is implied.
misericordiae = of mercy. Genetive. multae = of much. Genitive. Combining the two we get: of much mercy. You are of much mercy, you are very merciful, abounding in mercy.