{Because of an infirmity of the flesh} (di' astheneian t(8873)
sarkos). All that we can get from this statement is the fact
that Paul's preaching to the Galatians "the first time" or "the
former time" (	o proteron, adverbial accusative) was due to
sickness of some kind whether it was eye trouble ( 4:15 ) which
was a trial to them or to the thorn in the flesh ( 2Co 12:7 ) we
do not know. It can be interpreted as applying to North Galatia
or to South Galatia if he had an attack of malaria on coming up
from Perga. But the narrative in  Ac 13  14  does not read as if
Paul had planned to pass by Pisidia and by Lycaonia but for the
attack of illness. The Galatians understood the allusion for Paul
says "Ye know" (oidate).