David Kjos wants to know, "How do you interpret 1 Peter 3:21?"

My view of I Peter 3:21 is very simply...Baptistic.
The confusion comes when taking the verse by itself apart from the immediate context as well as the context of the rest of Scripture. When taken like this the verse seems to say that we are saved by the act of immersing ourselves in water.

In looking at this passage of Scripture it is best, as always, to look at context. What is the context? Peter has just told us that it is better to suffer for doing good than for doing bad. His proof is grounded in his view of the death and resurrection of Christ. Christ has already suffered for our sins, therefore, why should we suffer for them? Or put another way, since there is no more penalty from the Father for our sins, why subject ourselves to the penalty of man for sins by continuing to commit them?

For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit, in which he went and proclaimed to the spirits in prison, because they formerly did not obey, when God's patience waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight persons, were brought safely through water. Baptism, which corresponds to this, now saves you, not as a removal of dirt from the body but as an appeal to God for a good conscience, through the resurrection of Jesus Christ, who has gone into heaven and is at the right hand of God, with angels, authorities, and powers having been subjected to him. (1Pe 3:18-22)

Since we have already set the immediate context, we must also set the Scriptural context. Since Scripture will never contradict itself, it is useful for explaining itself. John the Baptist said,

"I baptize you with water for repentance, but he who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and with fire. His winnowing fork is in his hand, and he will clear his threshing floor and gather his wheat into the barn, but the chaff he will burn with unquenchable fire." (Mat 3:11-12)

John the Baptist in these words draws a distinction between the external act of baptism as a sign and the internal reality of baptism as being sealed by the Spirit for the believer and the judgment of God on the unbeliever. This seems to fit the illustration of the flood that Peter describes in his passage. Everyone who got wet in the flood died. And yet the flood was a means of deliverance for Noah and his family. The floodwaters that destroyed the earth were the same waters that lifted the Ark above the earth for the salvation of Noah.
Peter then says as much in his short explanation,

"not as a removal of dirt from the body but as an appeal to God for a good conscience."

In other words, NOT the external action of Baptism, but the internal action of faith and repentance towards God (conversion) which is prompted by the Holy Spirit. He further tells us that this is rooted not in our actions but Christ's actions performed in His death, burial, resurrection, and ascension.

We can also see the cross as a source of salvation for those who believe, but the same cross is a source of condemnation for those who reject Christ's work there. This is Peter's focus when he says that Christ is the Lord over all angels, authorities, and powers. Our comfort is that when we suffer for doing good, we have a just Lord in Heaven who will avenge us. This is also a cause for terror for unbelievers, because Christ has once suffered for sins, and without the appropriation of that work on their behalf, they will be punished all the more because of it.

Finally, in I Peter 4:1-2 Peter says this,

Since therefore Christ suffered in the flesh, arm yourselves with the same way of thinking, for whoever has suffered in the flesh has ceased from sin, so as to live for the rest of the time in the flesh no longer for human passions but for the will of God.
(1Pe 4:1-2)

Since Christ has suffered in the flesh, we also have suffered in His flesh. Baptism is an identification of ourselves with Christ's sufferings. We are made one with Christ through the baptism in the Spirit (not water baptism). We are baptized into Christ. Immersed in Him. When Christ suffered, Peter says that I am to think of myself as suffering. Since we suffered with Christ we should stop sinning.
On the other hand, every person who has ever lived will be baptized. Unbelievers will be baptized in the Lake of Fire for eternity, while believers are baptized by the Spirit into Christ who was baptized in the wrath of God on the Cross. Only those who are baptized into the Ark (Christ) are saved from God's wrath.

That's my position in a nutshell. There's also some exegetical stuff that no one wants to read through, if they're anything like me.

You may continue to send me your questions through the week and I will attempt to answer them.