After the buildup to declare his doctrine, Christ simply says that it is “whoso believeth in me, and is baptized, the same shall be saved; and they are they who shall inherit the kingdom of God.” That’s it. That is the doctrine that he gives. That this is the most important doctrine further highlights why Christ first authorized men to perform baptisms, and only after that did he begin to teach principles.
Although this seems simple, it is a condensed teaching. The first part is to “believe in [Christ].” That is not a request to acknowledge that he exists, but rather a command to covenant to follow what he teaches. Modern English sees belief as somewhat less than faith, but the New Testament uses the word believe when the underlying text has the verbal form of faith. English does not have a verb for faith. Christ is telling the people to have faith in him, but an active faith, one that has them do those things that he asks.
Baptism becomes the symbol of the covenant we make to be faithful to Christ’s teachings. This is the doctrine, not because there is no more to do, but because it encompasses all we should do. It is similar to Christ’s declaration that the two greatest laws are to love God with all our heart, and to love our neighbor as ourselves. Many like-minded teachings are condesned into these two briefly stated principles, or commandments. They are not the only things that we are to do, but they encapsulate the larger number of things that demonstrate that we have arrived at a point where we truly obey those two laws.
Verse 35 strongly echoes verse 32, thus forming bookends around the verses dealing with the things that are part of the doctrine.