The third stanza resolves the issue of whether the poet refers to himself (or humanity generally) or to Christ:

But yet thou stem of David’s stock when dry

And shriveled held, although most generous green was lopt

Whose sap a sovereign solder is, whereby

The breach repaired is in which it’s dropped.

Oh gracious twig! Thou cut off? Bleed rich juice

T’cement the breach, and glory’s shine reduce?

The “stem of David’s stock” can only refer to Jesus, who is the “Son of David” par excellence (“Jesus, Son of David, have mercy on me” Mark 10:47). 

The language of “stock” is a metaphor for a descendent. Thus, the development of the image of this stock=tree in terms of being dry or green sounds as if the poet were merely developing the metaphor at greater length. This is true, but there is also a direct reference to the words of Jesus in this same context.

There is a scene recorded in Luke’s Gospel of a conversation Jesus has with some women while being marched to Golgotha to be crucified:

Luke 23:27–31 (KJV)

27 And there followed him a great company of people, and of women, which also bewailed and lamented him. 28 But Jesus turning unto them said, Daughters of Jerusalem, weep not for me, but weep for yourselves, and for your children. 29 For, behold, the days are coming, in the which they shall say, Blessed are the barren, and the wombs that never bare, and the paps which never gave suck. 30 Then shall they begin to say to the mountains, Fall on us; and to the hills, Cover us. 31 For if they do these things in a green tree, what shall be done in the dry?

Thus the green tree cut, “although most generous green was lopt.” There is one further allusion contained within these lines:

Isaiah 53:2 (KJV)

      2       For he shall grow up before him as a tender plant,

      And as a root out of a dry ground:

      He hath no form nor comeliness;

      And when we shall see him, there is no beauty that we should desire him.

The concept here is that Christ is a green branch that was cut down and then dried as its sap runs out. 

The sap is a “sovereign solder”, a means of sealing together two broken parts. The sap in this instance is the blood of Christ lost in crucifixion. 

What is not immediately clear from the poem is what the solder repairs. The first two stanzas speak of a ruined palace/image. A palace is not repaired by means of a solder. The image of a solder repairs a break between two things. 

The image of solder seems to be drawn from (1) the sap=blood; (2) the break of the branch which bleeds; (3) and then the healing of the branch. The sap from the breach in the branch becomes the solder which heals the branch. 

Taylor does something fascinating here. The branch itself is healed by means of the sap which runs from the breach:

Whose sap a sovereign solder is, whereby

The breach repaired is in which it’s dropped.

Oh gracious twig! Thou cut off? Bleed rich juice

T’cement the breach, and glory’s shine reduce?

In particular note, “Bleed rich juice/T’cement the breach”. The blood spent heals the wound which caused the bleeding.  This makes for a fascinating theological point.

The death of Christ heals the breach between God and Man. In the body of Christ, the bridge and the breach between God and Man are manifest: Christ is God and Man, the mediator between the two. The death of the mediator heals the breach. 

But there is another level at work in Taylor’s poem: The death of Christ, the wounding of his body is the breach between God and Man. The cross is an assault upon God.

This is brought out by Psalm 2 which is a commentary upon the death of Christ:

Psalm 2:1–6 (KJV) 

¹           Why do the heathen rage, 

And the people imagine a vain thing? 

²           The kings of the earth set themselves,

And the rulers take counsel together, 

Against the Lord, and against his anointed, saying, 

³           Let us break their bands asunder, 

And cast away their cords from us. 

⁴           He that sitteth in the heavens shall laugh: 

The Lord shall have them in derision. 

⁵           Then shall he speak unto them in his wrath, 

And vex them in his sore displeasure. 

⁶           Yet have I set my king 

Upon my holy hill of Zion. 

The nations attack the Lord in the person of Christ, thinking to free themselves. But in so doing, rather than prevailing, they are witnesses to a coronation; the cross is a throne seen from the right perspective.

Taylor is working on this paradox with these lines: The wound is healed by the blood which flows from the wound. The death of Christ pays for the sin of killing Christ. The breaking of the body of the one who stands between God and Man heals the breach between God and Man. 

Taylor underscores the surprise of the breach being the repair by means of the meter:

Oh GRACious twig! THOU CUT-OFF? BLEED rich JUICE

The excess accented syllables requires one to show down to even say the words. 

Finally, Taylor makes good use of alliteration of D’s and S’s:

But yet thou stem of David’s stock when dry

And shriveled held, although most generous green was lopt

Whose sap a sovereign solder is, whereby

The breach repaired is in which it’s dropped.