WHAT mATTERS - CIRCUMCISION
Being circumcised did not make anyone a Jew. Circumcision was simply a sign that showed one's belief in the covenant of God. God made promises to Abram and his seed to come. Abram believed God would fulfill those promises, and his faith was imputed to him for righteousness. Abram's circumcision didn't make him a Jew, his faith made him a Jew and a recipient of the promises of God. All future Jewish males were commanded by God to be circumcised. This outward sign identified them with the covenant God had made with them. Abraham’s faith is what secured the covenant promises, and circumcision was the badge of identification as being a Jew and showed a serious desire to obey God.
Similarly, water baptism does not make anyone a Christian. Water baptism is simply a sign that shows one's belief in the covenant of God. God made a promise that whosoever would believe and trust in the death, burial, and resurrection of Jesus would receive eternal life. When a person believes that promise of God, his faith is imputed to him for righteousness. A person's water baptism does not make him a Christian, his faith makes him a Christian, and a recipient of the salvation promise of God. All Christians are commanded by God to be baptized. Our faith secures the covenant God makes with believers, and baptism is a sign of identification as being a Christian and shows a serious desire to obey God.
Water baptism is also an outward testimony of the Gospel. We identify with Jesus' death when we enter the drowning water. We show His burial when we go under that water. We show His resurrection when we come up out of the water. We show the sanctification process as we leave the water and continue our walk with Jesus on new ground. If you have not been water baptized since you have believed and been saved, it is time to be obedient in proclaiming to whom you belong.
 Genesis 17:7
 Romans 4:3
 Romans 4:11
 Genesis 17:10
 Titus 3:5
 Romans 1:16; 1 Corinthians 15:3,4
 Romans 10:10