A.T. Robertson Commentary 2 Corinthians 5:12

"We are not again commending ourselves unto you, but [speak] as giving you occasion of glorying on our behalf, that ye may have wherewith to answer them that glory in appearance, and not in heart." — 2 Corinthians 5:12 (ASV)

As giving you occasion of glorying (αφορμην διδοντες υμιν καυχηματος). An old Greek word (απο, ορμη, onset, rush), a base of operations, material with which to glory, as we say "a tip" only much more.

That ye may have wherewith to answer (ινα εχητε προς). Literally, "That ye may have something against (for facing those, etc.)." Paul wishes his champions in Corinth to know the facts.

In appearance, and not in heart (εν προσωπω κα μη εν καρδια). He means the Judaizers who were braggarts about their orthodox Judaism.