Article III: Of the Son of God.
1] Also they teach that the Word, that is, the Son of God, did assume the human nature in 2] the womb of the blessed Virgin Mary, so that there are two natures, the divine and the human, inseparably enjoined in one Person, one Christ, true God and true man, who was born of the Virgin Mary, truly suffered, was crucified, dead, and 3] buried, that He might reconcile the Father unto us, and be a sacrifice, not only for original guilt, but also for all actual sins of men.
4] He also descended into hell, and truly rose again the third day; afterward He ascended into heaven that He might sit on the right hand of the Father, and forever reign and have dominion over all creatures, and sanctify 5] them that believe in Him, by sending the Holy Ghost into their hearts, to rule, comfort, and quicken them, and to defend them against the devil and the power of sin.
6] The same Christ shall openly come again to judge the quick and the dead, etc., according to the Apostles’ Creed.
The Word of God is the Son of God, the Eternal Logos (John 1:1-18). He is one person but has two natures, human and divine. While analogies are imperfect the incarnation of our Lord is similar to unity of soul and body (Athanasian Creed), fire and iron (Formula of Concord), or the wave-particle duality of light (astrophysicist amateur theologians).
Christ must be Man in order to be a worthy sacrifice for men. After all only a righteous man could pay for the sins of another man by taking on those sins. Christ also has to be God due to the fact that while one perfectly righteous man may be able to pay for the sins of one sinful man, only God could pay for all the sins for all the men that will ever exist. Thus for Christ to be the true Lamb of God He must be both God and Man (John 1:19-34).
Christ is our Passover Lamb who causes the angel of death to pass over us. He died not only for Original Sin but Actual Sin as well. He pays the price for sin once for all. No further sacrifice is needed.
Jesus Christ also descended into hell, rose, and ascended as the creeds state. Now Christ from the throne of God the Father in heaven sends us the Holy Spirit to sanctify us. Sanctification is worked in us and delivered to us by the Holy Spirit but it is Christ’s sacrifice that grants us Sanctification. This is done because His holiness is now given to us as pure gift. So it is proper to say that Christ sanctifies us, just as much as the Holy Spirit does as well. Recall that the whole Trinity is involved in Sanctification even if the Holy Spirit is the primary actor.
This is the Apostolic faith and confession. The Reformers hold to nothing beyond this. Thus they are claiming to be orthodox by quoting the three Ecumenical Creeds. The Roman Confutation agrees with this article.
1 O love, how deep, how broad, how high,
Beyond all thought and fantasy,
That God, the Son of God, should take
Our mortal form for mortals’ sake!2 He sent no angel to our race,
Of higher or of lower place,
But wore the robe of human frame,
And to this world Himself He came.3 For us baptized, for us He bore
His holy fast, and hungered sore;
For us temptation sharp He knew;
For us the tempter overthrew.4 For us He prayed; for us He taught;
For us His daily works He wrought;
By words and signs and actions thus
Still seeking not Himself, but us.5 For us by wicked men betrayed,
For us, in crown of thorns arrayed,
He bore the shameful cross and death;
For us He gave His dying breath.6 For us He rose from death again;
For us He went on high to reign;
For us He sent His Spirit here
To guide, to strengthen, and to cheer.7 All glory to our Lord and God
For love so deep, so high, so broad;
The Trinity whom we adore
Forever and forevermore.(LSB 544)