Read Ephesians 4:4-6. A Muslim will say “I believe in God,” but for many reasons, the God in which he believes is not the “One God” of Scripture. Likewise, we read of one baptism. Men have changed many things since God revealed this baptism, resulting in other baptisms. The one baptism involves:

• one act: immersion (Romans 6:4). Another act [sprinkle, pour] results in another baptism.
• one element: water (Acts 10:47). Another element [“Holy Spirit”] results in another baptism.
• one authority: Jesus (Acts 2:38). Another authority [the magisterium of Catholicism, Methodist tradition] results in another baptism.
• one basis: body & blood of Jesus the Son of God (Romans 6:3). Another basis [blood of Jesus the archangel of “Jehovah Witnesses”] results in another baptism.
• one purpose: Changing the purpose for baptism results in a completely different baptism.