Adam Clarke on Matthew 9:31

But they - spread abroad his fame - They should have held their peace; for to obey is better than sacrifice, 1Sam 15:22; but man must always be wiser than God, however, it may be profitable to remark, 1st. That honor pursues those who fly from it. 2dly. He who is thoroughly sensible of God's mercy cannot long contain his acknowledgments. 3dly. That God in general requires that what a man has received, for his own salvation, shall become subservient to that of others - Let your light so shine, etc.

God chooses to help man by man, that all may be firmly knit together in brotherly love.