Concerning His mediatorship, the Scripture holds forth Christ’s call to His office; for¹ none takes this honor upon Him, but He that is called of God as was Aaron, it being an action of God, whereby a special promise being made, He ordains His Son to this office; which promise is, that Christ should be made a sacrifice for sin, that He should see His² seed, and prolong His days, and the pleasure of the Lord shall prosper in His hand;³ all of mere free and absolute grace towards God’s elect, and without any condition foreseen in them to procure it.

1. Hebrews 5:4–6 And no one takes this honor for himself, but only when called by God, just as Aaron was. So also Christ did not exalt himself to be made a high priest, but was appointed by him who said to him, “You are my Son, today I have begotten you”; as he says also in another place, “You are a priest forever, after the order of Melchizedek.”  ↩︎
2. Isaiah 53:10–11 Yet it was the will of the Lord to crush him; he has put him to grief; when his soul makes an offering for guilt, he shall see his offspring; he shall prolong his days; the will of the Lord shall prosper in his hand. Out of the anguish of his soul he shall see and be satisfied; by his knowledge shall the righteous one, my servant, make many to be accounted righteous, and he shall bear their iniquities.  ↩︎
3. John 3:16 “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life. Romans 8:32 He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things?  ↩︎