We must be fervent in what we have believed and abide in the doctrine of Christ and the apostles, and the big question is: What is the doctrine of Christ? All the doctrine of Christ is found in His Word: The Bible. And in it is all we need to live a correct Christian life, we do not need another way or a new revelation given by a person, His Word is enough and in it we sustain and remain.
The Bible talks about staying in the doctrine of Christ and it is John when he says:
9 Anyone who runs ahead and does not continue in the teaching of Christ does not have God; whoever continues in the teaching has both the Father and the Son.
10 If anyone comes to you and does not bring this teaching, do not take them into your house or welcome them.
11 Anyone who welcomes them shares in their wicked work.
2 John 1:9-11
God has called us to be persevering in the doctrine of His Word, and this perseverance is achieved by reading and studying the Scriptures, remember that one time Jesus said: “Search the Sacred Scriptures.” It is our duty to study the Bible, since through it we realize what is God’s good will for us, which is holy and perfect.