The Greek verb proskartereo (προσκαρτερέω) means to continue steadfastly in something, to devote oneself persistently to a task, or to wait on someone attentively. It combines pros (toward) + kartereo (to be strong/persist). It appears 10 times in the New Testament and describes the sustained, faithful devotion characteristic of early Christian community life and prayer.
Proskartereo is the vocabulary of persevering discipleship. Acts 2:42 — the charter of the early church — uses it four times: the believers 'devoted themselves (proskarterountes) to the apostles' teaching and to fellowship, to the breaking of bread and to prayer.' This is not occasional attendance but habitual, intentional commitment. Romans 12:12 lists 'faithful in prayer (te proseuche proskarterountes)' as the mark of the Spirit-filled life. The virtue described is not dramatic sacrifice but the quiet, consistent faithfulness that sustains the church across generations. The disciples 'joined together constantly in prayer' (Acts 1:14) before Pentecost — this posture of proskartereo prepared them for the Spirit's arrival.