That is a very good and necessary question, which very few in this world are able to answer.

Jesus said,
“Enter ye in at the strait gate: for wide is the gate, and broad is the way, that
leadeth to destruction, and many there be which go in thereat:
Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.”
Matthew 7:13,14

The Bible declares that God is a consuming fire; and he is also a covenant God. He made a covenant with Noah (Genesis 9). He made a covenant with Abraham (Genesis 15-17). He made a covenant with the children of Israel (Exodus 20). And during the time of the old testament, he said that he would make a new covenant with them, being that they had broken the first covenant.

“Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah: Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD: But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.”
Jeremiah 31:31-33

In the new testament, Paul the apostle of Christ quoted from this same passage, thus:

“…as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people.”
2 Corinthians 6:16

This came to pass when God poured out the Holy Ghost on 120 disciples, and then on about 3,000 more, on the day of Pentecost.

“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, as the Spirit gave them utterance.”
Acts 2:1-4

So, when the Holy Ghost was poured out and the new testament had begun, Peter and the rest of the apostles began to preach,

“Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. 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.”
Acts 2:38,39

To repent means to turn from your evil ways to God.

It means to stop doing what you are doing, and seek God in his word, and start to do things HIS WAY.

The only way that a man can understand the word of God, is to obey the word of God.

Jesus said,
“If any man will do his will, he shall know of the doctrine…”
John 7:17

And David wrote,
“The fear of the LORD is the beginning of wisdom:
a good understanding have all they that do his commandments.”
Psalm 111:9

And James wrote,
“But be ye doers of the word, and not hearers only, deceiving your own selves.”
James 1:22

Repentance is not something that a man does at one point in time, and then he can say that he has repented. Repentance is something that a man begins to do at a point in time, and then continues to do for the rest of his life. To be baptized in the name of Jesus Christ is to be baptized into Jesus Christ. It is to be buried with Christ, and to be risen again in newness of life.

“Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.”
Romans 6:3,4

Baptism in the name of Jesus Christ is for the remission (pardon, washing away) of our sins,

and it saves us.

“Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins…”
Acts 2:38

“He that believeth and is baptized shall be saved.”
Mark 16:16

“The like figure whereunto even baptism doth also now save us…”
1 Peter 3:21

“…according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost; Which he shed on us abundantly through Jesus Christ our Saviour.”
Titus 3:5

Baptism in the name of Jesus Christ is how we call upon the name of the Lord to be saved.

“Whosoever shall call upon the name of the Lord shall be saved.”
Romans 10:13

“And now, why tarriest thou? Arise and be baptized, and wash away thy sins, calling upon the name of the Lord.”
Acts 22:16

Receiving the Holy Ghost is part of the new testament baptism (of water and Spirit).

“Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.”
John 3:5

“…but ye are washed [in water baptism], but ye are sanctified [by the Holy Ghost], but ye are justified in the name of the Lord Jesus [by water baptism], and by the Spirit of our God [the Holy Ghost].”
1 Corinthians 6:11

And so, when we have the Spirit (the Holy Ghost),

and the water (water baptism in Jesus’ name),

THEN we have the blood (of Jesus Christ, to wash away our sins).

“And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.”
1 John 5:8

From the day that the new testament began, this is the way that a man can be made right with God, washed from his sins and made white as snow, by the blood of the Lamb of God, Jesus Christ our Lord.

And from that point, having been delivered from the power of darkness (Colossians 1:13), we abide in God’s word, keep ourselves unspotted from this world, and obey him in all things; and if we endure unto the end, we shall be saved from the coming wrath.

“And ye shall be hated of all men for my name’s sake: but he that shall endure unto the end, the same shall be saved.”
Mark 13:13

“To him that overcometh will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne.”
Revelation 3:21

Amen.