But ye, brethren, be not weary in well-doing (umei de, adelpoi, mh enkakhshte kalopoiounte). Emphatic position of umei in contrast to these piddlers. Mh and the aorist subjunctive is a prohibition against beginning an act (Robertson, Grammar, pp. 851-4). It is a late verb and means to behave badly in, to be cowardly, to lose courage, to flag, to faint, (en, kako) and outside of Luke 18:1 in the N.T. is only in Paul's Epistles ( 2 Thessalonians 3:13 ; 2 Corinthians 4:12 Corinthians 4:16 ; Galatians 6:9 ; Ephesians 3:13 ). It occurs in Polybius. The late verb kalopoiew, to do the fair (kalo) or honourable thing occurs nowhere else in the N.T., but is in the LXX and a late papyrus. Paul uses to kalon poiein in 2 Corinthians 13:7 ; Galatians 6:9 ; Romans 7:21 with the same idea. He has agaqopoiew, to do good, in 1 Timothy 6:18 .