If Jesus is omniscient, He foresees all of these problems and more. He foresees every abuse, every argument, every objection, and He still gives the command: “Be baptized and wash away your sins, calling on His name.” The same command to Saul is repeated to every believer.
Go into all the world and proclaim the Gospel to the whole creation. Whoever believes and is baptized will be saved, but whoever does not believe will be condemned (Mark 16:15-16).
Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit (Acts 2:38).
For in one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit (1 Corinthians 12:13).
For in Christ Jesus you are all sons of God, through faith. For as many of you as were baptized into Christ have put on Christ (Galatians 3:26-27).
God knows the works He excludes, and this is not one of them. The Father gives “all authority” to His Son (Matthew 28:18). In that context, the Son immediately uses His full authority to re-affirm that baptism is included: “Make disciples… baptizing them in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19).
Greek business papers from that time show that “in the name,” or more literally “into the name,” is a term for change of ownership. One owned by the world passes into God’s name, meaning into God’s possession. After biblical baptism one belongs to the Father, the Son and the Holy Spirit. Yes, Christ saves by faith, and this is where faith saves (Galatians 3:26-27; Mark 16:16; Acts 8:12). This is the “call” or “appeal” that is effective (Acts 2:21, 38). Why? Because God Himself ties this appeal to His Son’s saving death and resurrection (1 Peter 3:21).