Continue steadfastly (proskartereite). See note on Mar 3:9, note on Act 2:42, and Act 2:46 for this interesting word from pros and karteros (strong), common in the Koiné.
Watching (grēgorountes). Present active participle of grēgoreō, late present made on perfect active stem egrēgora with loss of ė, found first in Aristotle.