Practice is the positive equivalent of “Do not neglect” in the preceding verse. The word itself has the meaning “to attend to carefully,” “to put into practice” (so New Revised Standard Version), “to cultivate.” These duties is literally “these things” and most probably refers back to the immediately preceding verses, particularly verses 12-14. In certain languages it will be helpful to translate “Carefully put into practice the duties I have just mentioned.”

Devote yourself to them is literally “be in them,” with the meaning of being completely immersed or absorbed in these things. Appropriate equivalent idioms are “being up to his ears,” “being wrapped up,” “being immersed in,” or “throwing oneself into.” These two imperative verbs taken together make the command very emphatic.

The purpose of all this is so that all may see your progress (literally “your progress may be manifest [or, evident] to all”). All again refers to fellow Christians with whom Timothy has dealings. Progress includes the idea of advancement or furtherance; it is suggested by some that the word arose out of the practice of people cutting trees and shrubs in order to prepare the way for the advance of an incoming army. The progress being referred to here may refer to Timothy’s spiritual advancement in general (that is, his progress in the Christian life), or specifically to the development of the gifts and talents that are related to his function as a church leader.

An alternative translation model for this verse is:
• Carefully put into practice and give yourself completely to (or, immerse yourself in) these duties I have just mentioned, so that everyone will see how you grow in your life as a Christian.

Quoted with permission from Arichea, Daniel C. and Hatton, Howard A. A Handbook on Paul’s First Letter to Timothy. (UBS Handbook Series). New York: UBS, 1995. For this and other handbooks for translators see here .