Numeral adjective oktō (eight) in the New Testament

(Translation from NRSV with a few modifications for a more literal meaning)

Luke

2: 21After eight (oktō) days had passed, it was time to circumcise the child; and he was called Jesus, the name given by the angel before he was conceived in the womb.
9: 28Now about eight (oktō) days after these sayings Jesus took with him Peter and John and James, and went up on the mountain to pray.
13: 16And ought not this woman, a daughter of Abraham whom Satan bound for eight (oktō)een long years, be set free from this bondage on the sabbath day?"

John

5: 5One man was there who had been ill for thirty-eight (oktō) years.
20: 26And after eight (oktō) days his disciples were again in the house, and Thomas was with them. Although the doors were shut, Jesus came and stood among them and said, "Peace be with you."

Acts

9: 33There he found a man named Aeneas, who had been bedridden for eight (oktō) years, for he was paralyzed.
25: 6After he had stayed among them not more than eight (oktō) or ten days, he went down to Caesarea; the next day he took his seat on the tribunal and ordered Paul to be brought.

1 Peter

3: 20who in former times did not obey, when God waited patiently in the days of Noah, during the building of the ark, in which a few, that is, eight (oktō) persons, were saved through water.