Our Lord requires faith from those who invoke Him, not because He needs the assistance of others, (for He is both the Lord and Giver of faith,) but not to seem to bestow His gifts according to His acceptance of persons, He shews that He favours those who believe, lest they should receive benefits without faith, and lose them by unbelief. For when He bestows a favour, He wishes it to last, and when He heals, the cure to remain undisturbed.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Orat. in Pass. et Crucem. Dom. 4.