If we sin willfully (hekousiōs hamartanontōn hēmōn). Genitive absolute with the present active participle of hamartanō, circumstantial participle here in a conditional sense.
After that we have received (meta to labein). “After the receiving” (accusative case of the articular infinitive second aorist active of lambanō after meta).
Knowledge (epignōsin). “Full knowledge,” as in Heb 6:4.
There remaineth no more (ouketi apoleipetai). “No longer is there left behind” (present passive indicative as in Heb 4:9), for one has renounced the one and only sacrifice for sin that does or can remove sin (10:1-18).