Q. 12. Since then, by the righteous judgment of God, we deserve temporal and eternal punishment, is there no way by which we may escape that punishment, and be again received into favour?
God will have His justice satisfied: and therefore we must make this full satisfaction, either by ourselves, or by another.
 Exodus 20:5;  Deuteronomy 24:16; 2 Corinthians 5:14–15.
Q. 13. Can we ourselves then make this satisfaction?
By no means; but on the contrary we daily increase our debt.
 Job 9:2–3; and 15:14–16;  Matthew 6:12; Isaiah 64:6.
Q. 14.Can there be found anywhere, one, who is a mere creature, able to satisfy for us?
None; for, first, God will not punish any other creature for the sin which man hath committed; and further, no mere creature can sustain the burden of God’s eternal wrath against sin, so as to deliver others from it.
 Ezekiel 18:20;  Revelation 5:3; Psalm 49:8–9.
Q. 15. What sort of a mediator and deliverer then must we seek for?
For one who is very man, and perfectly righteous; and yet more powerful than all creatures; that is, one who is also very God.
 1 Corinthians 15:21; Romans 8:3;  Romans 9:5; Isaiah 7:14.
God is not only loving and merciful, He is also perfectly holy and just. Concerning His holiness, the prophet Habakkuk says: “Thou art of purer eyes than to behold evil, and canst not look on iniquity” (1:13). Similarly, the Apostle John says: “God is light, and in him is no darkness at all” (1 Jn 1:5). This means that God cannot tolerate sin, and no sinners can come into His favourable presence, who remain sinners in His sight. Moreover, as God is sovereign over the universe, and omniscient, we can expect Him to deal with sin rather than overlook them. The LORD Himself says in His Word: “I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me” (Ex 20:5), and “I will not justify the wicked” (Ex 23:7). Thus we can expect all sin to be punished no matter how minor they may appear to man. In order to satisfy the perfect justice of God, a sinner must either be punished for his sin himself, or someone else must be punished on his behalf.
Heidelberg Catechism >