Question: Scriptures say that we are saved by “Faith,” (Rom. 3:28), by “Grace” (Ephesians 2:8) and by “Baptism” ( 1 Peter 3:21) . . . how does all of that work together?
Answer: You have made an excellent observation regarding “faith”, “grace”, and “baptism”. However, it is not clear what you have observed about “baptism”. Are you claiming that faith, grace, and water baptism save a person? If so, then there is a misunderstanding of what “baptism” means in I Peter 3:21. Peter very clearly makes a distinction between two baptisms in I Peter 3:21. He says that the baptism which saves is not “… the putting away of the filth of the flesh,…” Instead, it is “… the answer of a good conscience towards God.” Water baptism is a picture of the believer’s faith being placed in Jesus Christ’s finished work and the resurrection to come for the new believer. It is a step of obedience, a good conscience towards God. There is zero Biblical indication that water baptism saves a person into eternal life. It is the baptism into the body of Christ (cf. I Corinthians 12:13), the baptism of the Holy Spirit, which saves a person. This baptism happens the moment a person trusts in the finished work of Jesus Christ for the payment of their sins.