From the late 100's A.D.:
The one who hung the earth in space, is himself hanged; the one who fixed the heavens in place, is himself impaled; the one who firmly fixed all things, is himself firmly fixed to the tree. The Lord is insulted, God has been murdered, the King of Israel has been destroyed by the right hand of Israel. - Melito of Sardis (died circa 180 A.D.), Paschal Homily
From one of the Desert Fathers:
He (Paul) then employed no subtlety or circumlocution, nor did he when he preached the gospel of the Lord blush at the mention of the cross of Christ. And though it was a stumbling-block to the Jews, and foolishness to the Gentiles to hear of God as born, God in bodily form, God suffering, God crucified, yet he did not weaken the force of his pious utterance because of the wickedness of the offence of the Jews: nor did he lessen the vigor of his faith because of the unbelief and the foolishness of others: but openly, persistently, and boldly proclaimed that He, whom a mother had borne, whom men had slain, the spear had pierced, the cross had stretched—was “the power and wisdom of God, to the Jews a stumbling-block, and to the Gentiles foolishness.” - John Cassian (circa 360-433 A.D.), On the Incarnation of the Lord (Against Nestorius) 3.8
As I have mentioned before, I believe that the apostolic church was divided at Chalcedon (451 A.D.), and that synods since then have not necessarily spoken for the whole apostolic church but only for parts of the church. With that in mind, it is interesting to see the official stand taken by the Chalcedonian churches (among these all the Western churches, plus the Eastern Orthodox). In the Second Council of Constantinople (often reckoned the 5th ecumenical council, 553 A.D.), the Chalcedonian churches sought to clarify the earlier findings of Chalcedon, whether the two natures of Christ were divisible (a semi-Nestorian construction possible under Chalcedon). The council's findings were:
If anyone does not confess that our Lord Jesus Christ who was crucified in the flesh is true God and the Lord of Glory and one of the Holy Trinity: let him be anathema. (Canon X, Second Council of Constantinople, 553 A.D.).In this age, the church is re-examining the early church and early doctrines to ensure everything is on solid ground. That is always the call of the God's people: to examine what we knows of Christ and to proclaim Christ to the world. The point of this post is simply that the proclamation of the Crucified God traces back to the early church and has been quite mainstream in the history of our proclamation of Christ.
If anyone shall say that the wonder-working Word of God is one [Person] and the Christ that suffered another; or shall say that God the Word was with the woman-born Christ, or was in him as one person in another, but that he was not one and the same our Lord Jesus Christ, the Word of God, incarnate and made man, and that his miracles and the sufferings which of his own will he endured in the flesh were not of the same [Person]: let him be anathema. (Canon III, Second Council of Constantinople, 553 A.D.).
To some it seems strange -- genuinely beyond understanding -- to proclaim God's suffering and death. To clear up this point so far as is possible, I will end where I began with Melito of Sardis from the late 100's A.D.:
When the Lord had clothed himself with humanity, and had suffered for the sake of the sufferer, and had been bound for the sake of the imprisoned, and had been judged for the sake of the condemned, and buried for the sake of the one who was buried, he rose up from the dead, and cried aloud with this voice: Who is he who contends with me? Let him stand in opposition to me. I set the condemned man free; I gave the dead man life; I raised up the one who had been entombed. Who is my opponent? I, he says, am the Christ. I am the one who destroyed death, and triumphed over the enemy, and trampled Hades under foot, and bound the strong one, and carried off man to the heights of heaven, I, he says, am the Christ.
Therefore, come, all families of men, you who have been befouled with sins, and receive forgiveness for your sins. I am your forgiveness, I am the passover of your salvation, I am the lamb which was sacrificed for you, I am your ransom, I am your light, I am your saviour, I am your resurrection, I am your king, I am leading you up to the heights of heaven, I will show you the eternal Father, I will raise you up by my right hand. - Melito of Sardis (died circa 180 A.D.), Paschal Homily
That is why we proclaim Christ crucified.