This is a subsidiary post of Grammatical, Syntactical, and Idiomatic Structures in the Scriptures.
It is also a subsidiary post of Vocabularies.
It is also a subsidiary post of Marriage and Family.
In Matthew 19:16-30 (see also Mark 10:17-31 and Luke 18:18-30), Jesus prophesied that anyone who left property or family for His sake would inherit even more property and an even greater family. We see fulfillment of this prophecy in the way that believers addressed one another from the very moment Jesus ascended into heaven: that is, as brothers and sisters (Acts 1:15-16). We also see fulfillment very soon thereafter when new believers began selling lands and houses so as to lay the proceeds at the apostles’ feet (Acts 4:34-35). (This was, by the way, a very practical step for the sellers since they knew from Jesus’ prophecy that Jerusalem was going to be destroyed, leaving ultimate land values in the region highly questionable.)
Jesus had also made clear in Matthew 12:46-50 (see also Mark 3:31-35 and Luke 8:19-21; 11:27-28) that true family was not physical but rather spiritual. That spiritual family would consist of those who “do the will of God” (“hear the word of God and do it”). Israel had been held together by its physical descent from Abraham all those centuries but going forward it would be held together by spiritual descent from Jesus. For this reason Paul could tell Timothy to treat the older men as fathers, the older women as mothers, the younger men as brothers, and the younger women as sisters (1 Timothy 5:2). These are the many mothers, fathers, sisters, brothers, and so on that Jesus had promised in Matthew 19:16-30 (Mark 10:17:31 and Luke 18:18-30). This is also consistent with what Jesus said in Matthew 23:8 – that all the disciples were brothers. Remember also that Jesus had told Peter that when he recovered from his denials of the Lord he should “strengthen his brethren” (Luke 22:32).
Let us therefore take note of how the wide vocabulary of family is used throughout the New Testament when believers refer to each other. All this is in fulfillment of what Jesus prophesied. It was in place from the resurrection onward. Like any lexicon or dictionary, I’ve organized the list alphabetically.
This list is not exhaustive. Just consider, for one example, the expression “born again” and its appropriate place in any catalog of familial terms used by New Testament believers.
brother – Matthew 19:29; 1 Timothy 5:1-2
child – 1 Timothy 1:2; Titus 1:4
children – Matthew 19:29; 3 John 1:4 (incl. “little children” as in 1 John 2:12)
elder – 1 Peter 5:1 (as contrasted with a younger man or brother)
father – Matthew 19:29; 1 Timothy 5:1-2
infant – 1 Corinthian 3:1; Hebrews 5:13
mature – Hebrews 5:14
mother – Matthew 19:29; 1 Timothy 5:1-2
sister – Matthew 19:29; 1 Timothy 5:1-2
young men – 1 John 2:13-14
younger men – 1 Peter 5:5 (as contrasted with an “elder” brother)
This way that believers had of addressing each other is prevalent in the New Testament letters and therefore must have taken root in that 15-20 year period (c.33 -50 AD) between the resurrection of Christ and the first letter. It’s hard to imagine that believers would have adopted this language apart from the teaching of Jesus, examples of which were given at the beginning of this post. Thus we should see Jesus Himself as the architect of this sort of vocabulary.