4:1 The Spirit clearly says that in later times [the time between Christ’s ascension and return] some will abandon [depart from; cf. Matt. 24:11; Acts 20:29-30] the faith and follow [pay attention to; devote oneself to] deceiving [Satan is the father of lies and deceptions; cf. Jn. 8:44] spirits and things taught by demons.
4:2 Such teachings come through [origin of teachings was demonic (4:1) but spread by people] hypocritical [those spreading error appeared to be devoted to Christ] liars, whose consciences have been seared [and therefore unable to distinguish truth from error] as with a hot iron.
4:3 They [note two prohibitions]  forbid people to marry [Paul never prohibited marriage]  and order them to abstain from certain foods [a prohibition which had no spiritual value or spiritual foundation; cf. Mk. 7:19], which God created to be received with thanksgiving by those who believe and who know the truth.
4:4 For everything God created is good, and nothing is to be rejected if it is received with thanksgiving,
4:5 because it is consecrated [“sanctified” or set apart] by the word of God [either God’s declaration that all is good (Gen. 1:31), the OT in general, or the Christian gospel message] and prayer [the table blessing offered in thanksgiving to God for His provision].
4:6 If you point these things out to the brothers, you will be a good minister [a servant leader] of Christ Jesus, brought up in  the truths of the faith and  of the good teaching [the biblical basis of his behavior] that you have followed.
4:7 Have nothing to do with godless [religiously bankrupt] myths [frivolous and not worthy of serious attention (Lea)] and old wives’ tales [inappropriate conversations; silly and empty talk]; rather, train [by means of spiritual disciplines; with the intensity, determination, and discipline of an athlete] yourself to be godly [we owe God both reverence and godly living].
4:8 For physical training [Gr. gumnaze from which we get our word gymnasium] is of some [but not as much as] value [see 1 Cor. 6:19-20 regarding stewardship of our bodies], but [by comparison; even more important than physical fitness; acknowledges that physical fitness should not be ignored] godliness has value for all things, holding promise for both the present life [even as we continue to age and physically deteriorate; see 2 Cor. 4:16] and the life to come [see 2 Cor. 5:1].
4:9 This is a trustworthy saying [the content of verse 8] that deserves full acceptance
4:10 (and for this we labor [strenuous toil] and strive [like an athlete; these words are a reminder that spiritual maturity is a pursuit]), that we have put our hope in the living God, who is the Savior of all men [does not mean that God automatically saves all people], and especially of those who believe [who respond to Him in faith].
4:11 Command [charge authoritatively] and teach [Christian doctrine] these things [see vv. 6-10].
4:12 Don’t let anyone look down on you because you are young [perhaps 30-35 years old; spiritual maturity, not physical maturity, is key to effective ministry; cf. Ps. 119:100], but set an example for the believers in speech, in life [daily behavior should be consistent with speech], in love [self-giving kind of love], in faith [or faithfulness] and in purity [maintain high moral standards].
4:13 Until I come, devote yourself to [ways to refute false teachings include…]  the public reading [because people did not have personal copies of the Scripture] of Scripture [i.e., the OT], to  preaching [exhortation; warn, advise, urge, and help listeners apply Scripture to daily lives] and to  teaching [formal instruction in Christian doctrine].
4:14 Do not neglect [don’t get into the habit of neglecting] your gift [probably exhortation and teaching], which was given you through a prophetic message when the body of elders laid their hands [symbolic acknowledgment, affirmation and recognition of the gift the Holy Spirit had given Timothy] on you.
4:15 Be diligent [keep on keeping on; bury yourself in] in these matters [doctrine and personal holiness]; give yourself wholly to them, so that everyone may see [recognize and be stimulated to personal growth] your progress [through speech, lifestyle, faith, and purity as per v. 12].
4:16 Watch [be spiritually alert and attentive] your life [holy living] and [sound] doctrine closely. Persevere [continue; stick to them] in them, because if you do [our beliefs and behavior matter], you will save [as opposed to “shipwrecked” in 1 Tim. 1:19] both yourself and your hearers [cf. Ps. 69:6].