Athanasius of Alexandria

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 shows 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.

Catena Aurea by Aquinas ↗

Bede

Or this is even to this day said by those who see the state of the synagogue so destitute that they do not believe it can be restored, and therefore think nothing of praying for its resurrection. But those things which are impossible with men are possible with God. Therefore said the Lord to him, Fear not, only believe, and she shall be made whole. (Luke 18:27.) The father of the girl is taken for the assembly of the doctors of the Law, which if it were willing to believe, the Synagogue also which is subject to it will be safe.

Catena Aurea by Aquinas ↗

Bonaventure

Second, as regards the strengthening of faith through divine persuasion, it is added: But Jesus, having heard this word, which namely could shake the mind of the ruler of the synagogue, because, according to that passage of Proverbs 26, "the words of a whisperer are as it were simple, and they penetrate to the innermost parts of the belly." Lest therefore the word of death penetrate within, he opposes the word of life; and this is the word that solidifies faith, because, in Hebrews 10, "my just one lives by faith; but if he withdraws …

Commentary on Luke, Chapter 8 ↗