The A.V. obscures the true sense. There is no article, and the emphasis is on promise. “I say 'a word of promise,' for a word of promise is this which follows.” Or, as Morison, “this word is one of promise.”
At this time (κατὰ τὸν καιρὸν τοῦτον)
Rev., according to this season. The reference is to Gen 18:14, where the Hebrew is when the season is renewed or revives; i.e., next year at this time. The season is represented as reviving periodically.