Ambrose of Milan — as excerpted in the Catena Aurea on Luke 5:12-16

“In falling upon his face he marked his humility and modesty, for every one should blush at the stains of his life, but his reverence kept not back his confession, he shews his wound, and asks for a remedy, saying, If thou wilt, thou canst make me clean. Of the will of the Lord he doubted, not from distrust of His mercy, but checked by the consciousness of his own unworthiness. But the confession is one full of devotion and faith, placing all power in the will of the Lord.”