5 Now the purpose of the commandment is love from a pure heart, from a good conscience, and from sincere faith, 6 from which some, having strayed, have turned aside to idle talk, 7 desiring to be teachers of the law, understanding neither what they say nor the things which they affirm. 8 But we know that the law is good if one uses it lawfully, 9 knowing this: that the law is not made for a righteous person, but for the lawless and insubordinate, for the ungodly and for sinners, for the unholy and profane, for murderers of fathers and murderers of mothers, for manslayers, 10 for fornicators, for sodomites, for kidnappers, for liars, for perjurers, and if there is any other thing that is contrary to sound doctrine, 11 according to the glorious gospel of the blessed God which was committed to my trust. 1 Timothy 1:5-11 (NKJV)
Carefully read the passage I placed at the top of this post. What is the aim of the charge of a true discipler? It is to produce the good fruit of love that issues from a pure heart and a good conscience and a sincere faith. That is the good fruit of genuine prophet of the Gospel of the Lord Jesus Christ. On the other hand, our Lord Himself told us in His Sermon on the Mount how to discern whether a prophet was false or not.