Baptism (full submersion in water, in the name of Jesus Christ, for remission of sins, by a GOD-ordained minister) is indeed a requirement.
Romans 6:3-5 tells us that Baptism is how we are linked to Jesus' death, and IF so linked to his death are also in expectation of his resurrection.
One way to understand the importance of baptism is to earnestly consider the importance of Jesus' death.
Jesus had sin on him (not that he sinned himself, but was carrying the burden of OUR sins). Death is what removed those sins from him. Jesus went down into death with sin on him...but he came up out of death without sin. That's what baptism (the likeness of Jesus' death) does for us. We go down into the water of baptism with sins...and come up without sins. (a.k.a born or made new)
Rom 6:3 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?
Rom 6:4 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.
Rom 6:5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection:
Love in Jesus to you all,
Kelby