The early Church speaks up 
Cyprian of Carthage: What unites the Church? (250 AD)(0)
Related:
The Martyrdom of Cyprian of Carthage
Since the Lord warns us, saying, “Ye are the salt of the earth,” and since He bids us to be simple to harmlessness, and yet with our simplicity to be prudent, then what else, beloved brethren, befits us than to use foresight and watching with an anxious heart, both to [...]
Justin Martyr describes Christian worship (c.150 AD)
I will relate the manner in which we dedicated ourselves to God when we had been made new through Christ; lest, if we omit this, we seem to be unfair in the explanation we are making. As many as are persuaded and believe that what we teach and say is true, and undertake to be able to live accordingly, are instructed to pray and to entreat God with fasting, for the remission of their sins that are past, we praying and fasting with them…
John’s disciple Ignatius writes to Christians in Asia Minor (107 AD)
The significance of these seven letters lies in their being intimate, familiar, and popular. They do not, in the first instance, reveal a set of ideas though they are not lacking in thoughtfulness. Rather they reveal a man. So much of early Christian literature is impersonal that it is refreshing to stumble upon letters reminiscent [...]