An average person has asked: “Why can’t humanity in and out of itself meet God’s requirement for removal of sin’s penalty? The Scriptures thoroughly present all that sets Jesus’ substitutionary work apart from any other attempted works to merit salvation from sin. Therein, we find all that Jesus had to be and do in order to be the suitable and acceptable substitute for sin.
The Bible teaches that Jesus was set apart before foundations of the world as a substitutionary payment for sin (Revelation 13:8). Peter discussed this truth with some detail when he wrote: For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your ancestors, 19 but with the precious blood of Christ, a lamb without blemish or defect. 20 He was chosen before the creation of the world, but was revealed in these last times for your sake. 21 Through him you believe in God, who raised him from the dead and glorified him, and so your faith and hope are in God. (Peter 1:18-21). Jesus Christ is presented in the Scriptures as the only one who met all requirements for the remission of sin – making it possible for humanity to come to God. At the beginning of Jesus’s ministry, John the Baptist testified about Him saying: “Behold, the Lamb of God, who takes away the sin of the world!”(John 1:29).
The doctrine of the person of Christ is crucial to the Christian faith. It is basic to soteriology [the study and/or understanding of salvation (from sin)], for if our Lord was not what He claimed to be, then His atonement was a deficient, not sufficient, payment for sin. Jesus plainly and exclusively declared that outside of His Person and work, there is no forgiveness of sin (John 8:24), and [lost, spiritually dead] humanity cannot come to God (John 14:6). Carefully surveying the life, work(s), words, and nature of our Lord Jesus Chist in the Scriptures, we find all His claims and declarations validated. To be our substitute, His personal nature, attributes, and work(s) must come together in a unique, yet non-contradictory, or confused way.
Let us go to the details of Jesus Christ’s personal nature, attributes and work(s) necessary for him as a savior. The scriptures affirm the following: (a). He must be fully God, (b). He must be fully man, (c). He must be sinless, (d). He must willingly provide Himself as a substitute, (e). He must conquer death.
 Ryrie, C. C. (1999). Basic Theology: A Popular Systematic Guide to Understanding Biblical Truth (pp. 272–273). Chicago, IL: Moody Press.