When Jesus was alive he said “I and my Father are one” and then later prayed in John 17: 20-21;
Neither pray I for these [apostles] alone, but for them also which shall believe on me through their word; That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
Paul later taught in regards to the unity of the spirit of God:
Ephesians 3:4-6There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all.
In the first century, life was physically very different from the life we know today. Yet the major happening on the day of Pentecost right after the ascension of Jesus Christ brought the unity of the spirit of God into the lives of willing people. Peter was the first to speak about what had happened. He did not have the whole picture yet but what God showed him he shared. The people had gathered from all across the known world at that time to celebrate one of three yearly feasts. Jerusalem had a huge population at this time of the year. Many of the people who responded to Peter’s magnificent sermon drastically changed their lives.
Acts 2:41-47 Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls. And they continued stedfastly in the apostles’ doctrine and fellowship, and in breaking of bread, and in prayers. And fear [respect] came upon every soul: and many wonders and signs were done by the apostles. And all that believed were together, and had all things common; And sold their possessions and goods, and parted them to all men, as every man had need. And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart, Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved.
Our culture is different today, but the unity of the spirit is the same. We don’t travel to the temple in Jerusalem to the feasts. We now have a written record of the apostle’s doctrine. We have the seven church epistles by Paul explaining the gift of holy spirit and what we are to think and do about it. We too can praise God and share in God’s grace in one with the thinking of the first century church!