{We stretch not ourselves overmuch} (ou huperekteinomen
heautous). Apparently Paul made this double compound verb to
express his full meaning (only in Gregory Nazianzen afterwards).
"We do not stretch ourselves out beyond our rights." {We came
even as far as unto you} (achri kai hum(936e) ephthasamen). First
aorist active indicative of phthan(935c), to come before, to
precede, the original idea which is retained in  Mt 12:28  ( Lu
11:20 ) and may be so here. If so, it means "We were the first to
come to you" (which is true,  Ac 18:1-18 ).