29 ¶ The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
Here we have John’s testimony, his record, his declaration of Jesus Christ. He is the sacrificial Lamb of God, who takes away the sins of the world, all past, present, and future, by His offering of Himself on the Cross. This is a fundamental tenet of Christianity and without belief in or trust in that doctrine you are lost.
Christ is the propitiation for our sins, appeasing the wrath of God for mankind’s iniquity, by His offering of Himself.
Romans 3:25 Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;
1John 2:2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world.
1John 4:10 Herein is love, not that we loved God, but that he loved us, and sent his Son to be the propitiation for our sins.
He is the ransom for our souls, a ransom paid to God for our sins.
Exodus 30:12 When thou takest the sum of the children of Israel after their number, then shall they give every man a ransom for his soul unto the LORD, when thou numberest them; that there be no plague among them, when thou numberest them.
Hosea 13:14 I will ransom them from the power of the grave; I will redeem them from death: O death, I will be thy plagues; O grave, I will be thy destruction: repentance shall be hid from mine eyes.
Matthew20:28 Even as the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
1Timothy 2:1 ¶ I exhort therefore, that, first of all, supplications, prayers, intercessions, and giving of thanks, be made for all men; 2 For kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty. 3 For this is good and acceptable in the sight of God our Saviour; 4 Who will have all men to be saved, and to come unto the knowledge of the truth. 5 For there is one God, and one mediator between God and men, the man Christ Jesus; 6 Who gave himself a ransom for all, to be testified in due time.
Through Christ atonement is made for sin and man is reconciled to God as per Romans 5:11.
Christ is God in the flesh, the Lamb of God; a sacrifice for sin, the sacrifice for sin, and your sacrifice for sin.
Genesis 22:8 And Abraham said, My son, God will provide himself a lamb for a burnt offering: so they went both of them together. (the prophetic import of this verse is underscored by the fact that it was actually a ram caught in a thicket that was provided for the immediate sacrifice in place of Isaac).
Exodus 12:3 Speak ye unto all the congregation of Israel, saying, In the tenth day of this month they shall take to them every man a lamb, according to the house of their fathers, a lamb for an house: 4 And if the household be too little for the lamb, let him and his neighbour next unto his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb. 5 Your lamb shall be without blemish, a male of the first year: ye shall take it out from the sheep, or from the goats:
Isaiah 52:13 through Isaiah 53:12 is one Old Testament view of the Christ to come.
Isaiah 53:5 But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed.
There is no other way for mankind to be saved from the great gulf of unquenchable fire that awaits his or her soul. There is only the Lamb of God, and nothing else.
Note - It wasn’t until the twelfth century AD rabbi called Rashi that the Jews began to look at Isaiah 53 as referring to, not the Messiah to come, but to the nation of Israel, as the suffering servant. (3)
(3) Joel E. Rembaum, “The Development of a Jewish Exegetical Tradition regarding Isaiah 53,” The Harvard Theological Review,Vol. 75, No. 3 (Jul., 1982), 294. http://www.jstor.org/stable/1509755.