Mat. 22:41While the Pharisees were gathered together, Jesus asked them, ⁴²Saying, What think ye of Christ? whose son is he? They say unto him, The Son of David. ⁴³He saith unto them, How then doth David in spirit call him Lord, saying, ⁴⁴The LORD said unto my Lord, Sit thou on my right hand, till I make thine enemies thy footstool? ⁴⁵If David then call him Lord, how is he his son? ⁴⁶And no man was able to answer him a word, neither durst any man from that day forth ask him any more questions.

Thesis – The Son of God, who himself is God, clothed himself with human flesh and nature, thereby becoming the Son of Man.

Jesus is both root and branch of David.

1. Branch

Isa. 11:1And there shall come forth a rod out of the stem of Jesse, and a Branch shall grow out of his roots:

Isa. 4:2In that day shall the branch of the LORD be beautiful and glorious, and the fruit of the earth shall be excellent and comely for them that are escaped of Israel. 

By branch is meant a descendent of David. A man who would sit on the throne of David and whose family tree would go back to Adam. [Adam ðSeth ðShem ð Abraham ð Isaac ð Jacob ð Judah ð David ð Messiah]

^{Adam & Eve through Seth
 Gen. 3:15}And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.

^{Shem
Gen 9:26}And he said, Blessed be the LORD God of Shem; and Canaan shall be his servant. ²⁷God shall enlarge Japheth, and he shall dwell in the tents of Shem; and Canaan shall be his servant.

^{Abraham, Isaac, Jacob
Gen 12:2}And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing: ³And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed.

Gen. 22:18And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.

^{Judah
Gen. 49:8}Judah, thou art he whom thy brethren shall praise: thy hand shall be in the neck of thine enemies; thy father’s children shall bow down before thee. ⁹Judah is a lion’s whelp: from the prey, my son, thou art gone up: he stooped down, he couched as a lion, and as an old lion; who shall rouse him up? ¹⁰The sceptre shall not depart from Judah, nor a lawgiver from between his feet, until Shiloh come; and unto him shall the gathering of the people be.

^{David
2 Sam. 7:8}Now therefore so shalt thou say unto my servant David, Thus saith the LORD of hosts, I took thee from the sheepcote, from following the sheep, to be ruler over my people, over Israel: ⁹And I was with thee whithersoever thou wentest, and have cut off all thine enemies out of thy sight, and have made thee a great name, like unto the name of the great men that are in the earth. ¹⁰Moreover I will appoint a place for my people Israel, and will plant them, that they may dwell in a place of their own, and move no more; neither shall the children of wickedness afflict them any more, as beforetime, ¹¹And as since the time that I commanded judges to be over my people Israel, and have caused thee to rest from all thine enemies. Also the LORD telleth thee that he will make thee an house. ¹²And when thy days be fulfilled, and thou shalt sleep with thy fathers, I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom. ¹³He shall build an house for my name, and I will stablish the throne of his kingdom for ever. ¹⁴I will be his father, and he shall be my son. If he commit iniquity, I will chasten him with the rod of men, and with the stripes of the children of men: ¹⁵But my mercy shall not depart away from him, as I took it from Saul, whom I put away before thee. ¹⁶And thine house and thy kingdom shall be established for ever before thee: thy throne shall be established for ever.

^{Messiah
Mat. 1:1}The book of the generation of Jesus Christ, the son of David, the son of Abraham.

2. Root

Isa. 11:10And in that day there shall be a root of Jesse, which shall stand for an ensign of the people; to it shall the Gentiles seek: and his rest shall be glorious.

Rev. 5:5And one of the elders saith unto me, Weep not: behold, the Lion of the tribe of Juda, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof.

Rev. 22:16I Jesus have sent mine angel to testify unto you these things in the churches. I am the root and the offspring of David, and the bright and morning star.

By root is meant the origin of David. Something more than just a man, more than a descendent of David – Creator God.

The root of David is seen in the plurality of the Godhead as God the Son. He is also known in the Old Testament as the Angel of the Lord.

Gen. 16:7And the angel of the LORD found her by a fountain of water in the wilderness, by the fountain in the way to Shur. ⁸And he said, Hagar, Sarai’s maid, whence camest thou? and whither wilt thou go? And she said, I flee from the face of my mistress Sarai. ⁹And the angel of the LORD said unto her, Return to thy mistress, and submit thyself under her hands. ¹⁰And the angel of the LORD said unto her, I will multiply thy seed exceedingly, that it shall not be numbered for multitude. ¹¹And the angel of the LORD said unto her, Behold, thou art with child, and shalt bear a son, and shalt call his name Ishmael; because the LORD hath heard thy affliction. ¹²And he will be a wild man; his hand will be against every man, and every man’s hand against him; and he shall dwell in the presence of all his brethren. ¹³And she called the name of the LORD that spake unto her, Thou God seest me: for she said, Have I also here looked after him that seeth me? ¹⁴Wherefore the well was called Beerlahairoi; behold, it is between Kadesh and Bered.

Mal. 3:1 Behold, I will send my messenger, and he shall prepare the way before me: and the Lord, whom ye seek, shall suddenly come to his temple, even the messenger of the covenant, whom ye delight in: behold, he shall come, saith the LORD of hosts.

Other Old Testament declarations of the Messiah as God -

Psa. 110:1 The LORD said unto my Lord, Sit thou at my right hand, until I make thine enemies thy footstool.

Isa. 7:14Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.

Isa. 9:6For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. ⁷Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the LORD of hosts will perform this.

Heidelberg Catechism
Q13: Can we ourselves make this satisfaction?
A13: Certainly not; on the contrary, we daily increase our guilt.[1]

1. Job 9:2-3; 15:15-16; Matt. 6:12; 16:26

B.    No creature can satisfy the eternal penalty our sins deserve.

Heidelberg Catechism
Q14: Can any mere creature make satisfaction for us?
A14: None; for first, God will not punish any other creature for the sin which man committed;[1] and further, no mere creature can sustain the burden of God's eternal wrath against sin [2] and redeem others from it.

1. Heb. 2:14-18
2. Psa. 130:3

C.    Only an eternal being, God himself, can satisfy the penalty of our sins.

Heidelberg Catechism
Q17: Why must He also be true God?
A17: That by the power of His Godhead He might bear in His manhood the burden of God's wrath,[1] and so obtain for [2] and restore to us righteousness and life.[3]

1. Isa. 53:8; Acts 2:24
2. John 3:16; Acts 20:28
3. I John 1:2

Heidelberg Catechism
Q16: Why must He be a true and righteous man?
A16: Because the justice of God requires [1] that the same human nature which has sinned should make satisfaction for sin; but one who is himself a sinner cannot satisfy for others.[2]

1. Rom. 5:15
2. Isa. 53:3-5

1 Tim. 2:5For there is one God, and one mediator between God and men, the man Christ Jesus; ⁶Who gave himself a ransom for all, to be testified in due time.