How can a person come to God?

 The answer is found in the verse directly below.

1st Pet 3:18 For Christ also suffered once for sins, the just for the unjust, that He might bring us to God, being put to death in the flesh but made alive by the Spirit,

In the above verse, we see the reason Jesus came to the earth, and suffered on the cross, it was once for sins.  He is just, and we are unjust. Meaning, Jesus was innocent, faultless and guiltless. We were unrighteous, and sinful. So, Jesus who is innocent, died on the cross for those who were guilty of sin.

The reason He did this, was "that He might bring us to God" People often wonder about why Jesus came to the earth, but here's the answer in black and white. It was so that He could bring us to God. 

The word bring, means, to lead, to open a way of access, for one to God. To make one acceptable to God. To approach God. 

Jesus Himself said, concerning Himself,   “I am the way, the truth, and the life. No one comes to the Father except through Me. John 14:6

So, this is why He came and died on the cross, and it's how we can come to God, it's through Jesus, it's by putting our faith in Him. He wants to bring you to God. 

A few last comments about the remaining verses in 1st Peter 3:19-22 See those verses below.....

1st Pet 3:19 by whom also He went and preached to the spirits in prison,

1st Pet 3:20 who formerly were disobedient, when once the Divine longsuffering waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight souls, were saved through water.

1st Pet 3:21 There is also an antitype which now saves us--baptism (not the removal of the filth of the flesh, but the answer of a good conscience toward God), through the resurrection of Jesus Christ,

1st Pet 3:22 who has gone into heaven and is at the right hand of God, angels and authorities and powers having been made subject to Him.

Three things are being said here. 

#1. Jesus preached to the spirits in prison. The word preached here, is not the same word as used to speak of preaching the gospel, so as to invite people to be saved. But, rather, it's used here simply to speak of a proclamation of fact. Jesus went and proclaimed to the spirits of those who had died before He came, but were unbelievers, He went to where they were being held ( and are there today by the way ) and He announced His death on the cross, and His rising from the dead, and the victory that brought over sin. 

#2. In mentioning water, Peter then explains that water baptism, does not saved you, but, it's a symbol of having died with Christ, and then risen, it's something one does in obedience to the command of Jesus, and it shows that they have come to Christ for salvation, and are now in a new life in Christ. 

#3. Jesus is now in heaven, seated to the right of the Father, and the angels and authorities, and powers have been made subject to Him. He is the Lord of Lord's, and is in control of all that exists anywhere, and in all places. 

Thank You Lord for this blessed chapter. 

Application/Promise

1. Jesus will bring you to God if you let Him.

2. He is the only way to God. 

3. Believing in Jesus means, you will be brought to God.

4. Jesus has paid for your sins.

5. You don't need to pay for your sins.

6. But, you must believe in Christ now, to go to the Father.

7. Have you believed in Jesus?

8. Will you do it now?

9. He will bring you to the Father if you let Him.