Salvation By "Blood"
God made man with the capacity to serve and glorify Him, or to rebel at His will. Without free-agency man's service would be meaningless; but the power of choice makes man subject to punishment when he sins. In fact, untempered justice demands that man be punished for his sin; but Our Father is merciful, and gave of Himself- His Only Begotten Son- that both justice and mercy might be fully satisfied.
This is the basis for the NT doctrine of salvation in Christ's blood. The "blood" under consideration is not the red and white corpuscles; the plasma, hemoglobin, fibrinogen, etc., that make up blood per se. This ridiculous explanation is justified only by equally ridiculous conceptions of mystical powers in Christ's blood (Ex. "One drop could save the world!"). The significance of Christ's blood is its relation to life -- Christ gave Himself -- he willingly died on Calvary for the sins of the world.
The special place that blood had in the Jewish sacrificial system is due to its relation to life. In LEV.17:10-f. the people were forbidden to eat blood, "For the life of the flesh is in the blood; and I have given it to you upon the altar to make atonement for your souls; fir it is the blood that maketh atonement by reason of the life".
Man sinned, and "it repented Jehovah that he had made man on the earth" -- so man was the one due to die. But God planned to send His Son to die in man's stead (ISA.53:4-f). As a type or shadow of this perfect offering, God directed animal sacrifice from early times (HEB.11:4); the life of the offering in place of the life of the sinner. A dramatic demonstration of this principle is seen in the account of the offering of Isaac (GEN.22:1-f); with God providing a ram in the place of Abraham's son. Even the name of the place has significance -- "Jehovah-jireh" (God will provide). And after 1,500 years of blood-shedding in Judaistic types, the "pattern" was given reality, the shadow its substance (HEB.9:22-f) in the offering of Jesus Christ, "once for all" (HEB.10:10). There is no more "bloody" sacrifice -- the types have served their purpose. But man still sins and is "proven" (see GEN.22:1,12) not by the first of his flocks, nor even his son; but by offering himself a living sacrifice unto God (ROM.12:1).
Jesus said, "If any man will come after me, let his deny himself -- ") (MAT.16:24). He calls on us to die -- yes, die to the old life of sin and rebellion against God. "How shall we, that are dead to sin, live any longer therein? Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life" (ROM.6:2-4).
When gospel preachers say one "contacts the blood of Christ in genuine NT baptism" they are not referring to some mystical "blood in the tank". Christ is the "author of eternal salvation unto all them that obey Him"