When did it ECHAD change? Part I

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שמע ישראל יהוה אלהינו יהוה אחד
Shema Yisrael Adonai Eloheinu Adonai Echad (ONE or ALONE).

It is often taught, both in Judaism and in Christianity, that our Creator is Echad (one), but the definition of Echad in each religion vastly differ from one another. Both religions however, do not take different viewpoints until generations AFTER the death of Yeshua. In fact, from the Old Covenant perspective, neither religion strays away from the same theology of a true Echad (ONE) G-d. That is, He is ONE. It was only several centuries AFTER the birth of Yeshua that the meaning of the ONE G-d started to take a different path.

In the 4th and 5th centuries paganistic ideas of the deity rose among the early Christians; this brought much attention to the so-called church fathers who then decided to add their own view on the deity subject. In 451 CE, at the Council of Chalcedon, it was decided what the "Catholic" position regarding the nature of Messiah would be. Here is what they decided:

“The Messiah is both fully God (deity) and fully man (human)!”

The council of Chalcedon, 451 states:

"Therefore, following the holy Fathers, we all with one accord teach men to acknowledge one and the same Son, our Lord Jesus Christ, at once complete in Godhead and complete in manhood, truly God and truly man, consisting also of a reasonable soul and body; of one substance [homoousios] with the Father as regards his Godhead, and at the same time one substance with us as regards his manhood; like us in all respects, apart from sin; as regards his Godhead, begotten of the Father before the ages, but yet as regards his manhood begotten, for us man and for our salvation, of Mary the Virgin, the God-bearer [Theotokos]; one and the same Christ, Son, Lord, Only-begotten, recognized in two natures, [en dyo physesin] without confusion, [asynchytos] without change, [atreptos] without division, [adiairetos] without separation [anchoristos]; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and substance [hypostasis], not as parted or separated into two persons, but one and the same Son and Only-begotten God the Word, Lord Jesus Christ; even as the prophets from earliest times spoke of him, and our Lord Jesus Christ himself taught us, and the creed of the Fathers has handed down to us."