The Greek adverb diapantos (διαπαντός) means always, continually, or at all times — literally 'through all (time).' It is used in Hebrews 9:6 of the priests who 'entered continually (diapantos) into the first section of the tent,' performing their regular duties, and in Acts 10:2 of Cornelius who 'prayed to God at all times.'
Diapantos speaks of uninterrupted, habitual devotion. In Hebrews 9–10, the continual (diapantos) offerings of the old covenant are contrasted with the once-for-all (ephapax) sacrifice of Christ. The priests' repetitive, never-finished work highlights the inadequacy of animal sacrifice — they entered the sanctuary diapantos because the work was never done. But Christ, having made one perfect sacrifice, sat down (Hebrews 10:12) — His work complete. Meanwhile, the believer's response is the diapantos of Cornelius: continual prayer and the diapantos of praise (Hebrews 13:15) — the 'sacrifice of praise to God continually.'