"There will be a time when they will not endure sound teaching ; but having ears that itch, they will gather up doctors according to their own lusts, and they will turn away their ears from the truth and turn to the fables. But you, be sober in everything, endure sufferings, do the work of an evangelist, fully perform your service." 2 Timothy 4: 3-5
We see every day around us that the prophetic word of Paul is already a reality today. In his time, the bad teachings began to spread : while claiming to be Christians, some questioned the resurrection, others reverted to the Law of Moses, others claimed they were not obliged to work to ensure own subsistence, etc.
When he writes this letter, Paul knows that he finishes his service and passes the relay to Timothy, his child in faith. He encourages her to preach the good news without getting tired. Timothy then had only A.T. at its disposal, and not in the convenient form that we know. Therefore, he had to have at hand a copy, "a model" of the teachings he had received (2 Tim.1: 13).
Appreciate the privilege of possessing the entirety of the Bible. It is submission to God and His Word that can keep us from bad teachings. Let us take account of the whole Word of God, for the characteristic of bad teaching is to emphasize one aspect of divine truth to the detriment of others equally important. Let us read the Word of God with the light of the Holy Spirit so as not to twist it by human thoughts.
Paul points out that we always tend to bring out what is right in the Word. The legalistic will find incentives to separate from the others for the most futile reasons; the worldly man will gladly declare that all things are permitted to him ; the mystic will apply himself to making his body judged evil suffer ; the exalted will feel pushed by a spirit from which weighting and common sense are absent, etc.
Some false teachings existed in the time of the apostles. That gave them an opportunity to warn us. But Satan does not disarm to disturb or seduce believers. Let us not judge doctrine by preachers, but judge preachers by doctrine. Our safeguard is therefore to attach ourselves to the whole Word of God and to read it in the dependence of the Holy Spirit.
Source (To pleasing the Lord)