1 Corinthians 9:8

Say I these things as a man? or saith not the law the same also? (KJV)

Then: Believing that he still needed to reinforce the point, Paul directed information about the Jewish law (knowledge) towards the Jews and towards those who admire knowledge. The verse is transitional.

Now: Drawing on many avenues of support - including everyday experience and the law - to support rhetorical points is good argument procedure. Choosing points which connect to the knowledge of a particular audience is a smart way to present and defend beliefs.