Church Tradition
Church tradition refers to the written and oral teachings handed down from Christ, the Apostles and those they trained to lead the Early Church. Studies vary but only about 25% or less of the Roman population at the time of Christ we fully literate. So, the majority of teaching about the church was done by oral teaching and preaching.

The Bible and the Early Church Fathers clearly state that oral teaching is as authortative as written instruction:
And the things that thou hast heard of me among many witnesses, the same commit thou to faithful men, who shall be able to teach others also.
[Paul in 2 Timothy 2:2]
Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.
[Paul in 2 Thessalonians 2:15]

The Apostles at the first Church Council at of Jerusalem claimed guidance from the Holy Spirit [Acts 15:28] in their official decisions. This reflects the promise of Christ concerning their ability to teach correctly guided by the Holy Spirit [John 14:26] and which St. Paul affirms by calling the Church the pillar and ground of the truth [1 Timothy 3:15]. Later writers, usually called 'Church Fathers', who explained the Church's teachings or displayed skill in gaining a deeper understanding of complex theological issues, were used by the Holy Spirit to continue to guide the Church. The final authority of the Church is an Ecumenical Council which brings together all of the leaders (Bishops) of the Church, just like that at Jerusalem in AD 51.

Christ clearly states the importance of keeping His teachings and commandments [John 14:23-24] for salvation. I would be very confused and concerned if He had not taken steps to insure that I, over two millennium later, would have a trustworthy source to rely on to know what those teachings and commandments were and how to correclty apply them in my life. That source is the Church. And, in this modern information age I can even verifty the consistency of those teachings myself by reading the Bible and writings of the Church Fathers.


Additional Reference
Church Tradition
Excepts from Scripture and Early Writings