Albert Barnes Commentary Galatians 4:13

"but ye know that because of an infirmity of the flesh I preached the gospel unto you the first time:" — Galatians 4:13 (ASV)

Ye know how. To show them the folly of their embracing the new views which they had adopted, he reminds them of past times, and particularly of the strength of the attachment which they had shown for him in former days.

Through infirmity of the flesh. Greek, Weakness, (asyeneian) Compare See Barnes on 1 Corinthians 2:3; See Barnes on 2 Corinthians 10:10; See Barnes on 2 Corinthians 12:7.