This text contains an admonition from the apostle to the young evangelist to be faithful to the word of God. While this is certainly an important aspect of the preacher’s work, it is equally applicable to every Christian.
The first phrase “the pattern of sound words” indicates what many refuse to accept, that God’s word contains a pattern or blueprint that Christians are to follow. “Pattern theology” is ridiculed today, but is certainly advocated by Paul in this text. As Adam Clarke wrote in his commentary, “No man was left to invent a religion for his own use, and after his own mind. God alone knows that with which God can be pleased.”
The second phrase “that good thing which was committed to you” indicates the effectual nature of God’s word. It is “profitable” and able to “complete” the man of God (cf. 2 Timothy 3:16-17).
Timothy was to be a good steward. He was to “hold fast” to that which was “committed to” him. We have the same obligation.