Adam Clarke on Matthew 8:3

Jesus put forth his hand - I will; be thou clean - The most sovereign authority is assumed in this speech of our blessed Lord - I Will: there is here no supplication of any power superior to his own; and the event proved to the fullest conviction, and by the clearest demonstration, that his authority was absolute, and his power unlimited. Be thou cleansed, καθαρισθητι; a single word is enough.

And immediately his leprosy was cleansed - What an astonishing sight! A man whose whole body was covered over with the most loathsome disease, cleansed from it in a moment of time! Was it possible for any soul to resist the evidence of this fact? This action of Christ is a representation of that invisible hand which makes itself felt by the most insensible heart; of that internal word which makes itself heard by the most deaf; and of that supreme will which works every thing according to its own counsel.