The remnant is to teach and preach to the "lost sheep of the house of Israel".
jesus taught them the gospel and sent them to teach us the gospel
“And Jesus came and spake unto them, saying,
All power is given unto me in heaven and in earth.
Go ye therefore, and
teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.”
Matthew 28:18-20 KJV
“And he said unto them,
Go ye into all the world, and preach the gospel to every creature. He that
believeth and is baptized shall be saved;
but he that
believeth not shall be damned.”
Mark 16:15-16 KJV
Salvstion was preached by Jesus to them and ordained for them to go teach the same things to the world and people still today hear thier witness because it’s written
“how shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, ( Jesus )
and was
confirmed unto us by them that heard him; ( the apostles and disciples )
God also bearing them witness, both with signs and wonders, and with divers miracles, and gifts
of the Holy Ghost, according to his own will?”
Hebrews 2:3-4 KJV
that’s why Paul and Peter healed people and rose the dead as they were witnessing the gospel because the spirit of Christ was in the Confirming the truth that hey we’re confirming that Jesus had taught and commanded them to preach to all People beginning at Jerusalem for salvation of all Mankind past present and future
The message of the gospel
“and said unto them, Thus it is written, and thus
it behoved Christ to suffer, and to rise from the dead the third day: ( Paul preached that )
and
that repentance and remission of sins should be preached in his name among all nations,( Paul preached That ) beginning at Jerusalem. And
ye are witnesses of these things.”( that’s why Paul was witnessing these things until he was killed by Nero )
Luke 24:46-48 KJV
“And Paul dwelt two whole years in his own hired house, and received all that came in unto him, preaching the kingdom of God, and teaching those things which concern the Lord Jesus Christ, with all confidence, no man forbidding him.”
Acts 28:30-31
That’s the last you hear about Paul and then you read his final Letter when he was about to face Nero the second time. The church kept preaching the gospel long after Paul died he was one of them believer of the gospel which is the reason he gave his entire existence to preaching it to all people