Timothy needed to be cautious about choosing church leaders. [source][source][source]
"In assessing people, errors are unavoidable." [1][source]
Sin is not always obvious as soon as someone practices it. However eventually it will become known if persisted in, normally. In the same manner good deeds can remain hidden for years. Consequently the better a church knows its potential elders the fewer surprises they will present after their appointment. [source][source][source]