Would have Logos incarnated if the ancestral sin had not been committed?
If yes - what for?
I would advise to read chapter 4(God as Man) of ‘The Orthodox Way’ by bishop Kallistos Ware. The answer to this question is on page 70-71. It’s good to read this book completely, I like it this book very much.
http://books.google.nl/books?id=HG8c-lUZIDEC&printsec=frontcover&dq=orthodox+way+kallistos+ware&source=bl&ots=pqqGo1Ja1U&sig=yiXKMyQ5ihO0Dw0MDIKcY8WGVXs&hl=nl&ei=9UOTTYeQI8yZOvSzrIkB&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDQQ6AEwAw#v=onepage&q=incarnation&f=false If no - did humans make God incarnate? Was God forced by us?
This is what I would like to share with you, I made this text in my attempt to explane the wonder of Incarnation to moslims, when we conversed about it. I welkom every comment or feedback concerning this text.
Why do we need incarnate God, in the person of Jesus Christ?
1. Out of His love God the Almighty has created the whole world with all that is in it. He has made the sun, the moon and the stars to shine upon the face of the earth. He made living creatures, the plants and the animals, that they may praise Him, as the Psalmist says. At the end He created also a man to be the head and the crown of His creation. He placed him in the most beautiful garden called Eden. Our first ancestors, Adam and Eve, had been living a gracious and blissful life.
2. Nonetheless in order to let them prove their faithfulness, God commanded them not to eat the fruit from a certain tree called the tree of the knowledge of good and evil. Alas, being deluded by devil the men transgressed the command given them by God. So it came to pass what the Lord has spoken: for in the day that you eat of it you shall die. The men were expelled from the paradise to lead a hard life outside of it, before they die and return to the dust where out they were taken.
3. In this world after the primordial sin nobody were able to redeem the children of Adam from this desperate state, not a righteous person, not an angel, nobody except God alone. Nobody could bring the men back to the paradise, because curse fell upon all the descendants of Adam.
4. Because by the sin of the first men curse fell upon all their descendants, in the same manner there was a need in a Man who could restore the fault of the first man, and, contrary to Adam, become the firstling of those who are to be saved. It is logical that this Man, second Adam, must be without any sin, completely loyal to the will of God. But there was nobody who could be free from the curse of the primordial sin. Even the most righteous persons were in need of salvation from this anxious state.
5. Nothing and nobody could redeem humanity if God had not redeemed it. So the All merciful God took pity on us. God the Son, the only begotten Son of God the Father, equal and coeternal with God the Father and the Holy Spirit, took our human nature in order that we might become sons and daughters of God by His grace. Jesus Christ, the incarnate Word of the Father, took our sins and our curse upon Himself (as a Man, sinless Man), being nailed on the cross that we may become partakers of His everlasting and blessed life,’kingdom of priests and holy nation’(like the Scripture says). On the third day after His death on the cross He rose up, ascended into Heaven (as a Man) to sit nigh God the Father. From there he will come again to judge the living and the departed (the general Resurrection), and His Kingdom will have no end.
6. He established His holy Church, poured down the grace of the Holy Spirit upon its members, the apostles (and other members of the Church), who brought the Good News into many parts of the earth, baptizing many people of various nations in the Name of the Father and of the Son and of the Holy Spirit. Every man is thus welcom to be a partaker in the Kingdom of God.
May be this link would be useful as well.
www.orthodox.net/nativity/nativity-sjok-2.html 
