What would you call the body of Christ? There is one baptism, it is spiritual in nature because every believer is with repentant faith and is in Christ, since each came to Christ, they all have this baptism. The command for baptism was the command to Go and baptize those of every nation, those ones coming to Christ, and those who do submit to that outward expression with water used when it's available being baptized are not the ones fulfilling the command for that. There are a few without the baptism of water who still have the one baptism, the thief who was dying on a cross next to Jesus and repented is an example for that.
The body of Christ is not what I would call it, but rather what it is according to the bible: the church
Baptism is not for the purpose of an outward demonstration of anything to anyone. It's to be washed of your sins, to become a member of the body of Christ, the church. Who was present when the Ethiopian eunuch was baptized by Philip as recorded in Acts 8? Just him and Philip; so, who was it an outward expression to, Philip? That's utter nonsense.
And you have no understanding of the thief on the cross as it relates to baptism: it doesn't have any correlation to baptism whatsoever! Jesus was yet alive when he made the promise to the thief and forgave him. So, the need for baptism was not an issue. Baptism did not become a requirement until after the Lord's death. See below a short dissertation on this subject previously posted here and elsewhere.
REPOST
I continually encounter people trying to justify that baptism is not an absolute necessity for one's salvation by use (erroneously) of the thief on the cross as justification, as he was not baptized but yet saved by the Lord, which is true! BUT, the error in this is the lack of understanding of the scriptures. You must read and understand Hebrews 9:15-17 which clarifies why the thief on the cross was saved by Jesus without being baptized. Christ was still alive when this occurred meaning it was done while the old testament or covenant was still in effect; the new testament had not yet been established because Christ had not yet died. And since the Lord was still alive no one could possibly be baptized into Christ under NT salvation criteria. Baptism did not become a requirement as part of salvation until the new testament began which was after the death of Christ. Jesus forgave the thief on the cross no different than he forgave others during his earthly ministry, such as the woman caught in the act of adultery as recorded in John 8. Baptism should not even be an issue when discussing the thief on the cross, but unfortunately always is, but in error.
Hebrews 9:15-17
15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
16 For where a testament is, there must also of necessity be the death of the testator.
17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth.