On the day of his ascension, Jesus told the disciples to “wait for the promise of the Father” Acts 1:4
Jesus said, “I send the promise of my Father upon you..you will be endued with power from on high” Luke 24:49. Then “Jesus having received of the Father the promise of the Holy Spirit” shed it forth. Acts 2:33.
The promise is of the Father because it comes from the Father. Jesus said that he came from the Father.
“I came forth from the Father” John 16:28
“I came out from God” John 16:27
“I came out from Thee [Father]” John 17:8
“I proceeded forth and came from God” John 8:42
He is the “Word that proceeds from the mouth of God” Matt 4:4
He is the “teacher come from God” John 3:2.
He has seen the Father because he is from God. John 6:46.
Jesus said, “I am from Him” John 7:29.
Paul says that “we receive the promise of the Spirit through faith” Gal 3:14.
“The promise of Jesus Christ was given to them that believe by faith” Gal 3:22
“Through the Spirit we wait for the hope of righteousness by faith” Gal 5:5
“For this cause I bow my knees unto the Father of our Lord Jesus Christ,
Of whom the whole family in heaven and earth is named (the family of God),
That He would grant you…to be strengthened with might by His Spirit in the inner man;
That Christ may dwell in your hearts by faith” Eph 3:14-17
The Father strengthens us with the power of His Spirit (mind) dwelling in our minds, our inner man; which enables Jesus to dwell in our minds by believing he is the Son of God who came from the Father. The Spirit of God in the inner man is Christ dwelling in our heart. His presence in our minds makes it possible for us “to comprehend the breadth, and length, and depth, and height; and to know the love of Christ, which surpasses knowledge, so that we might be filled with all the fullness of God” Eph 3:18, 19. The Spirit of Christ affects our minds, our comprehension, our understanding.
When the Spirit of Christ dwells in our minds, not only are we united with him, but we are united with each other because we share the same mind of Jesus. “We are called with all lowliness and meekness, with longsuffering, forbearing one another in love; endeavoring to keep the unity of the Spirit in the bond of peace.” Eph 4:1-3. “One body (the body of Jesus, the church), and one Spirit (the mind of Jesus), even as you are called in one hope of your calling” verse 4. Who is the one hope of our calling?
“Christ in you, the hope of glory” Col 1:27.
“Hope in our Lord Jesus Christ” 1Thes 1:3.
“The blessed hope and glorious appearing of the great God and our Savior Jesus Christ” Titus 2:13.
“We have a hope as an anchor of the soul which enters into that within the veil” Heb 6:19.
Jesus is our Hope. He has entered within the veil into the most holy place.
“He is a better hope that makes perfect by which we draw near to God” Heb 7:19.
He is better than the angels, better than Moses, better than Melchisedec. He is able to make us perfectly united with him. And when we are united with God’s Son, we can through him draw near to his Father.
“We have an anchor that keeps the soul steadfast and sure though the billows roll.
Fastened to the Rock which cannot move: grounded firm and deep in the Saviour’s love”
So, there is one body: Christ’s. There is one Spirit: Christ’s. There is one hope: Christ.
And “one Lord, one faith, one baptism” all Christ Jesus, the Promise of the Father.
“He that is joined unto the Lord is one spirit” 1Cor 6:17. Our spirit is united with his Spirit.
What does it mean to have the same spirit? Paul said that “Titus and I walked in the same spirit, we walked in the same steps” 2Cor 12:18. “We should walk even as he walked” 1John 2:6. We follow him.