The Old Testament is filled with the old covenant. The New Testament bring the New Covenant. As believers in Jesus Christ, we are under a new covenant now. It’s one where He leaves us His will and His testament. 1 Corinthians 11: 25 In the same way, after supper he took the cup, saying, “This cup is the new covenant in my blood; do this, whenever you drink it, in remembrance of me.” Understand that the new covenant is sealed by the Blood of Jesus. In Genesis 9 we read how God says He places the rainbow in Heaven, as token of His covenant to never flood earth again. He also says when He sees the rainbow, He will remember His covenant. God always gives a token/symbol to look at for Him and us to remember we share a covenant. Just like the ring represent a marriage between a husband and wife. Genesis 17: 10 - 11 This is my covenant with you and your descendants after you, the covenant you are to keep: Every male among you shall be circumcised. You are to undergo circumcision, and it will be the sign of the covenant between me and you. The old covenant spoke of a physical circumcision which was needed to be in covenant with God. Once again, the circumcision is a sign as we read in the above scripture. When God saw that, He remembered His covenant with them. If the sign wasn’t there, then there was nothing reminding God that He has a covenant with you. When God looks at people, He is looking at that sign; that token. Without the covenant people are without God in this world. Genesis 17: 7 7 And I will establish my covenant between me and you and your offspring after you throughout their generations for an everlasting covenant, to be God to you and to your offspring after you.  God has made a covenant with Abraham and his offspring. Abraham’ offspring now is all who receive Jesus Christ as their Lord and Savior. Colossians 2: 9 - 12 For in Christ all the fullness of the Deity lives in bodily form, 10 and in Christ you have been brought to fullness. He is the head over every power and authority. 11 In him you were also circumcised with a circumcision not performed by human hands. Your whole self ruled by the flesh[b] was put off when you were circumcised by[c] Christ, 12 having been buried with him in baptism, in which you were also raised with him through your faith in the working of God, who raised him from the dead. In the new covenant our token is to be baptized with water and the Holy Spirit. When we do so, God looks at us and see that, He looks to us and remember the promises we have in Jesus Christ. By being in Jesus, which is the seed of Abraham, we have the benefits and promises of the old covenant, still in the new covenant. We have the same promises that Abraham had. The faith of a reborn child of God, is what makes us righteous in Him. As David remembered the covenant God has with him, he had the full confidence that God will come through and deliver Goliath, who was not circumcised, there for not in covenant with God, into the hands of David. May all believers have that confidence as we go through life.