1 tn Grk “The greeting in my hand, Paul, which is a sign in every letter, thus I write.”
sn Up to 3:17 the letter was dictated by Paul but written down by a secretary or amanuensis. But Paul took up the pen and wrote vv. 17-18 personally to authenticate that it was his (how I write in every letter). See similar indications in 1 Cor 16:21; Gal 6:11; and Col 4:18.