{Beyond their power} (para dunamin). "Alongside" with
accusative like huper dunamin in  1:8 . Field (_Ot. Nov_.)
quotes Josephus (_Ant_. iii. 6, 1) for kata dunamin and para
dunamin as here. Few give kata dunamin (according to actual
ability). Paul commends this high pressure collection because of
the emergency. {Of their own accord} (authairetoi). Old verbal
adjective (autos, hairetos from haireomai, to choose), of
their own initiative, voluntary. Only here and verse  17  in N.T.
Papyri often have hekousi(9373) kai authairet(9373) (willingly and
voluntarily).