The First Council of Nicaea was a council of Christian bishops convened in the Bithynian city of Nicaea (now İznik, Turkey) by the Roman Emperor Constantine I. The Council of Nicaea met from May until the end of July 325.
This ecumenical council was the first of many efforts to attain consensus in the church through an assembly representing all Christendom. Hosius of Corduba may have presided over its deliberations.
Attended by at least 200 bishops, its main accomplishments were
➛ the settlement of the Christological issue of the divine nature of God the Son and his relationship to God the Father,
➛ the construction of the first part of the Nicene Creed,
➛ the mandating of uniform observance of the date of Easter.
-- Wikipedia
Taking the issues decided by the council individually:
- Who Jesus is - They missed it. Jesus is not the Son of God in the human sense. Jesus is God incarnate - Immanuel. Jesus is God and there is only 1 person in the 'godhead' (otherwise we are serving some multi-headed, polytheistic nightmare).
- The Creed - They missed it - for the same reason they missed understanding who our God is,
- Easter - They missed it as Jesus was crucified on Apr 25th and rose again on Apr 28th (evening) not on different days of the year.
In general the problem with Catholicism and the councils which served to formulate it is that it resulted in confusion about God and the strangling of the potential of Christianity to manifest as intended, authorized and empowered by Christ Jesus.
➛ There is One God who is One Person who is Christ Jesus.
➛ The intent of Christ is that we be like Him.
➛ The authority of Christ is given to us by His Word.
➛ The power of Christ is given to us by His Holy Spirit.
Essentially the men who met and made decisions to bind all of Christianity were motivated - not by a concern for souls and Truth - but by a desire to control and manage the Body Of Christ.
Christ is the head of His Body and each of us are members in particular. There are no members more important than any other members. We are all Joint Heirs with Christ, we are all His brothers and we are all Sons Of God.
But prideful men, though believers, did not trust the Holy Spirit who is eternal God manifesting in the Body of Christ Jesus to lead believers. So, they effectively replaced the Spirit ( Holy Spirit) and Truth ( Word Of Christ) with their rules, their doctrines, their catechisms.
This left the Power Of God and the Word Of God on the sidelines as theologians determined what the believers should hear, what the believers should believe and what the believers should do.
Not believing in the authority of the Word and the power of the Holy Spirit to manage the Body is their great sin.
We see it today as the Catholic Church does not promote Christ. Rather it promotes the Church. The reason is that it does not believe in any dynamic, living relationship of Christ with His believers.
Effectively, it denies an intimate, personal relationship with God, substituting a man-made religious organization in its place.
Nothing good came out of Nicea.