1 Timothy 4:6-8

If you point out these instructions to the brothers and sisters, you will be a good servant of Christ Jesus, constantly nourished [through study] on the words of the faith and of the good [Christian] doctrine which you have closely followed. But have nothing to do with irreverent folklore and silly myths. On the other hand, discipline yourself for the purpose of godliness [keeping yourself spiritually fit]. For physical training is of some value, but godliness (spiritual training) is of value in everything and in every way, since it holds promise for the present life and for the life to come.