Tu dominaris potestatis maris :
motum autem fluctuum eius tu mi-
tigas .
Tu humiliasti sicut uulneratum su-
perbum : in brachio uirtutis tue dis-

In a modern biblical layout, this would read:

Tu dominaris potestatis maris: motum autem fluctuum eius tu mitigas.
Tu humiliasti sicut uulneratum superbum: in brachio uirtutis tue dis[persisti inimicos tuos.]

Translation from the Douai version of the Bible:
[Psalm 88, verses 10-11]

Thou rulest the power of the sea:
and appeasest the motion of the waves thereof.
Thou hast humbled the proud one, as one that is slain:
with the arm of Thy strength Thou hast [scattered Thine enemies.]