If a man knoweth not (ε τις ουκ οιδεν). Condition of first class, assumed as true.

How to rule (προστηνα). Second aorist active infinitive of same verb προιστημ and with οιδεν means "know how to rule," not "know that he rules."

How (πως). Rhetorical question expecting negative answer.

Shall he take care of (επιμελησετα). Future middle of επιμελεομα, old compound (επ, direction of care towards) verb, in LXX, in N.T. only here and Luke 10:34.

The church of God (εκκλησιας θεου). Anarthrous as in verse 1 Timothy 3:15, elsewhere with article (1 Corinthians 10:32; 1 Corinthians 15:9; 2 Corinthians 1:1; Galatians 1:13). The local church described as belonging to God. No one in N.T. but Paul (Acts 20:28) so describes the church. This verse is a parenthesis in the characteristics of the bishop.