The word discipline in I Timothy 4:7 literally means to exercise naked. In other words, Paul is telling Timothy that he must not hide things from those who are in leadership over him. But as Paul clearly states in 4:15, Take pains with these things; be absorbed in them, so that your progress will be evident to all." It is clear that we as Believers are to be completely occupied with our spiritual growth. In the process of doing this, we will as Paul says later in Romans 11:14- if somehow I might move to jealousy my fellow countrymen and save some of them." So let's move unbelievers to jealousy by our godly conduct and righteous fruit of the spirit everyday.