When God inspired one preacher to write a letter of instruction and encouragement to another preacher, the Lord made it abundantly clear that He had only one message to be taught and obeyed – neither the preacher nor the adherents were to deviate from His narrow course. They were to “teach no other doctrine” (1 Tim. 
1:3). To emphasize the singularity and definitive nature of this doctrine, notice how many definite articles are associated with His one message:
“a true son in the faith…contrary to the sound doctrine…according to the glorious gospel… concerning the faith…come to the knowledge of the truth…speaking the truth…the mystery of the faith…boldness in the faith…ground of the truth…depart from the faith…know the truth… sanctified by the word…nourished in the words of the faith and of the good doctrine…take heed to the doctrine…denied the faith…labor in the word and doctrine…for the Scripture… does not consent to the doctrine…destitute of the truth…strayed from the faith…fight the good fight of the faith…strayed concerning the faith” (all in First Timothy).
The Lord only has one truth, one doctrine, one way. Are you following it?