Say I these things as a man?
&c.] After the manner of men, reasoning from things common among men, and obvious to everyone's observation:
or saith not the law the same also?
As the subject the apostle is upon was capable of being illustrated and confirmed by instances common unto, and easy of observation among men; so it might be supported by divine authority; it was not only a clear point from the reason of things, but was certain by the law of God.