We know and have looked at the grand purpose of God to save us from all of eternity to HIS praise with all of history flowing from His counsel "in the fullness of time." We now look at our Mediator who is our Lord Jesus Christ and see that God designed redemption around the Mediator and designed the Mediator to "fit" exactly our needs for just that. God's justice and our inability to fulfill it!
Our impossibility: Is there any way God's justice can be appeased and return us to His favor. This is a crucial question. We look at our character and God's character of being both righteous and just. No one can sin against God with impunity. God does not wink at sin or overlook it. When we sin against each other we destroy character....impossible with God! His justice must be satisfied! But how can we make that satisfaction? We sin against the ETERNAL God. The kind of Mediator we need touches us in our inability to make satisfaction and God's great mercy to us in two fold fashion. Israel in the old testament knew they were cursed and could never satisfy for their sins. There is no salvation apart from Christ as we stand in need of His grace, being totally depraved, and having sin continually cleaving to us which touches God.
God's only way: Salvation is a gift of God! Faith and grace are GIFTS. Christ fills the void and not only teaches us about ourselves but the granger of our redemption! Christ must satisfy the two prong requirement being very God and very man. If you deny either one of these natures in Christ you have NO salvation! In the old testament the priest could never make himself the sacrifice. Moses wanted to be cursed of God for the people, but it was not possibly with him being only man. Even we would not punish someone else for the sins of another. Yet, satisfaction for sin must be made. All the blood of bulls and goats in the old testament could not pay for a single sin, yet they were required to make sacrifice themselves for their sins being only a picture.
Graciously given: The promised seed who is our Lord Jesus Christ took the law and fulfilled it in His human nature being human yet very God. Many want to make Him only a man, but hell would have swallowed Him up if that was the case. But He was very God and could cry out "It is finished" on the cross as He satisfied man's requirement and God's justice against sin. The living God not only designed sin and grace, but every detail therein and dove tails everything perfectly in Christ Jesus our Lord that no one can boast but can only give all glory and praise to HIM both now as we live and into all of eternity as we continue our new life!
Praise be to God for such a salvation! "Amazing grace how sweet the sound, that save a wretch like me!"