"Beloved, while I was making every effort to write you about our common salvation, I felt the necessity to write to you appealing that you contend earnestly for the faith which was once for all handed down to the saints. 4 For certain persons have crept in unnoticed, those who were long beforehand marked out for this condemnation, ungodly persons who turn the grace of our God into licentiousness and deny our only Master and Lord, Jesus Christ." (Jude 3-4)The early church, much like today, existed in the midst of many troubles. There were troubles from without, such as persecutions and lies regarding them, and trouble from within, such as heresies and schismatics. The Kingdom of God is always advancing, though not without difficulty requiring faith, discipline, and effort. Jude had hoped to write a letter to the brethren enjoining them to fully embrace the common salvation that was the birth right of all true believers. A salvation that was more than a deliverance from hell but also a deliverance to heaven, heath, wholeness, preservation, and protection. However, circumstances had arrived forcing him to change his plans.
Long ago God had warned about those who would rise up to pervert the faith and fidelity of many and to cause the children of God to fall away from their love and worship of God.
"If a prophet or a dreamer of dreams arises among you and gives you a sign or a wonder, and the sign or the wonder comes true, concerning which he spoke to you, saying, 'Let us go after other gods (whom you have not known) and let us serve them,' you shall not listen to the words of that prophet or that dreamer of dreams... But that prophet or that dreamer of dreams shall be put to death, because he has counseled rebellion against the Lord your God who brought you from the land of Egypt and redeemed you from the house of slavery, to seduce you from the way in which the Lord your God commanded you to walk" (Deuteronomy 13:1-5)Jesus too warned us about such deceivers. "For false Christs and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect. Behold, I have told you in advance." (Matthew 24:24-25) Paul, later, would also warn the churches he established, saying, "I know that after my departure savage wolves will come in among you, not sparing the flock; and from among your own selves men will arise, speaking perverse things, to draw away the disciples after them. Therefore be on the alert." (Acts 20:29-31)
It is to be expected that, from time-to-time, false teachers and false prophets will arise, even from within the church, to teach perverse things and to lead God's people astray, but we ought not to submit to them or suffer them to continue in their error. Knowing these things shall happen, we must be diligent in our faith, not giving heed to new and novel doctrines that tend towards disputes and the ruin of the hearer. We must contend for the faith we have received rather than looking for another or for some new revelation and innovation to faith. The faith we have has been once and for all delivered to us by our Lord and His apostles; our apostles in the faith. It was delivered complete and we have no need for any new instruction. Tertullian wrote,
"For in as far as what was delivered in times past and from the beginning will be held as truth, in so far will that be accounted heresy which is brought in later. But another brief treatise will maintain this position against heretics, who ought to be refuted even without a consideration of their doctrines, on the ground that they are heretical by reason of the novelty of their opinions" (Tertullian, Book 1, Chapter 1, Against Marcion)Our efforts, our hopes, and our trust ought to remain with the faith once and for all delivered and we should shun all new attempts to modify, modernize, or replace it. We must contend for what we have already received knowing that it was delivered to us by Jesus and His Apostles. This message we can trust, this message we can build our lives upon. All new "apostles," who preach a message not consistent with the one we have received, we should ignore and give no attention to. We already have God's message, now its up to us to simply live it.