A clear conscience toward God

1 Peter 3:18-4:6
Those who were disobedient long ago when God waited patiently in the days of Noah while the ark was being built. In it, only a few people, eight in all, were saved through water, and this water symbolizes baptism that now saves you also—not the removal of dirt from the body but the pledge of a clear conscience toward God.
Therefore, since Christ suffered in his body, arm yourselves also with the same attitude, because whoever suffers in the body is done with sin. As a result, they do not live the rest of their earthly lives for evil human desires, but rather for the will of God.
For this is the reason the gospel was preached even to those who are now dead, so that they might be judged according to human standards in regard to the body but live according to God in regard to the spirit.
Who are the spirits in prison? Are they unbelievers who have died; Old Testament believers who have died; fallen angels?
What did Christ preach? Was it a second chance for repentance; the completion of his redemptive work; final condemnation?
The flood-water which destroyed the world saved Noah and his family by floating the ark, so Peter sees the water of baptism as a symbol of rescue from death. It was the ark, not the water, which really saved Noah - as it is the risen Christ, bot baptism in itself, who saves those who trust him and are cleansed from sin.
Why?
Preach gospel has a little people obey it like the Noah day, only eight people were saved.
God will judge all dead and live people, but for those who follow Christ suffering will be saved.
Since Christ suffered in his body, arm yourselves also with the same attitude, because whoever suffers in the body is done with sin. So we may stand firm and live for the will of God.
No one has an excuse that I did not hear the gospel. If we preach gospel continues.
Basically, we should have a clear conscience toward God. 
How?
Let me have a clear conscience toward God.