He declares that, having witnessed the Fall of the Persecutors, he now rejoices at the Peace enjoyed by the Christians
And it is surely a happy circumstance that the punishment of such persons as I have described should have been publicly manifested in our own times. For I myself have witnessed the end of those who lately harassed the worshipers of God by their impious edict. And for this abundant thanksgivings are due to God that through his excellent Providence all men who observe his holy laws are gladdened by the renewed enjoyment of peace. Hence I am fully persuaded that everything is in the best and safest posture, since God is vouchsafing, through the influence of their pure and faithful religious service, and their unity of judgment respecting his Divine character, to gather all men to himself.
Source: Life of Constantine (New Advent)