{Confirming} (epist(8872)izontes). Late verb (in LXX), in
N.T. only in  Ac 14:22  15:32,41 , to make more firm, to give
additional (epi) strength. Each time in Acts the word is used
concerning these churches. {To continue in the faith} (emmenein
t(8869) pistei). To remain in with locative, old verb. It is
possible that pistis here has the notion of creed as Paul uses
it later ( Col 1:23  with epimen(935c);  1Ti 5:8 ). It seems to be
here more than trust or belief. These recent converts from
heathenism were ill-informed, were persecuted, had broken family
and social ties, greatly needed encouragement if they were to
hold out. {We must} (dei h(886d)(8373)). It does not follow from this
use of "we" that Luke was present, since it is a general
proposition applying to all Christians at all times ( 2Ti 3:12 ).
Luke, of course, approved this principle. Knowling asks why
Timothy may not have told Luke about Paul's work. It all sounds
like quotation of Paul's very language. Note the change of
construction here after parakalountes (infinitive of indirect
command, emmenein, but hoti dei, indirect assertion). They
needed the right understanding of persecution as we all do. Paul
frankly warned these new converts in this heathen environment of
the many tribulations through which they must enter the Kingdom
of God (the culmination at last) as he did at Ephesus ( Ac
20:20 ) and as Jesus had done ( Joh 16:33 ). These saints were
already converted.