1. The promise of the Father and the baptism of the Holy Spirit are one and the same thing.
Luk 24:49 And, behold, I send the promise of my Father upon you: but tarry ye in the city of Jerusalem, until ye be endued with power from on high.

Act 1:4,5 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me. For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.

Act 1:8 (YLT) but ye shall receive power at the coming of the Holy Spirit upon you, and ye shall be witnesses to me both in Jerusalem, and in all Judea, and Samaria, and unto the end of the earth.

Act 2:33 Therefore being by the right hand of God exalted, and having received of the Father the promise of the Holy Ghost, he hath shed forth this, which ye now see and hear.

2. The baptism of the Holy Spirit is a fulfillment of a prophecy by Joel.
Act 2:17, 18 And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy:

Joe 2:28, 29 And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions: And also upon the servants and upon the handmaids in those days will I pour out my spirit.

3. The baptism of the Holy Spirit was not forgiveness of sins but empowerment to be witnesses.
Act 1:8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judea, and in Samaria, and unto the uttermost part of the earth.

4. The world (unsaved) can’t receive the promised Spirit, but only the children of God.
Joh 14:17 Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you

5. The disciples were children of God as their names were written in heaven.
Luk 10:20 Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven.

6. The promise of the Father could not come until Christ left this world.
Joh 16:7 Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.

7. The disciples were to wait in Jerusalem for the promise of the Father.
Act 1:4, 5 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me. For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.

8. The account in scripture where the disciples receive the promise of the Father.
Act 2:1-4 And when the day of Pentecost was fully come, they were all with one accord in one place. And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting. And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Ghost, and began to speak with other tongues [languages], as the Spirit gave them utterance.

9. The promise of the Father is not only for the early disciples but for all that are called.
Act 2:39 For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.

10. Disciples in Ephesus were water baptized and afterward they received the promise of the Holy Spirit.
Act 19:1, 5, 6 And it came to pass, that, while Apollos was at Corinth, Paul having passed through the upper coasts came to Ephesus: and finding certain disciples, When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues [languages], and prophesied.

11. The Holy Spirit is given to the children of the Father that ask.
Luk 11:9, 10, 13b And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you. For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened. …how much more shall your heavenly Father give the Holy Spirit to them that ask him?

12. The Holy Spirit is received by faith.
Act 15:8, 9 And God, which knoweth the hearts, bare them witness, giving them the Holy Ghost, even as he did unto us; And put no difference between us and them, purifying their hearts by faith.