This prayer is found in the Gregorian Sacramentary and many other manuscripts. In 1570 it was the Collect for the Sunday in the Octave of Christmas. The 1970 revisers sought out prayers for the Christmas season more clearly suited to its themes.
This brief text is very difficult to translate, as discrepancies among the versions in pre-conciliar hand-missals clearly demonstrate. The heart of the problem is the verb mereamur. In classical Latin, mereor means 'I earn' or 'I deserve'. Mereor is very common in liturgical texts, but theology teaches us that we cannot earn or deserve God's gifts. To think otherwise is the heresy of Pelagianism, to refute which Saint Augustine said 'when God crowns our merits, he is crowning his own gifts'.
How, then, should we translate mereamur? That is not an easy question to answer, and I do not offer a complete answer here. But I should welcome comments and suggestions from readers of the blog.
The prayer under discussion is unusual: the verb mereor in liturgical texts usually has God's reward as its object, as when we pray the we may 'merit the rewards of the blessed'. But here, we pray 'that we may deserve to abound in good works', to borrow Fr Adrian Fortescue's translation.
When preparing a new translation, ICEL proposed . . . that in the name of your beloved Son we may be made rich in good works. The passive 'be made' was intended to indicate that our good works are God's gift. The Vox Clara committee rejected this, so that now we pray that we may abound in good works. This leaves mereamur untranslated.
We shall need to speak about mereor again as we make our way through the liturgical year.