Whenever discipline is needed in any area of life, it requires sacrifice. A key ingredient in any effort to “discipline yourself for godliness” is a willingness to sacrifice. One cannot truly be godly without a spirit of sacrifice. The apostle Paul even went so far as to declare a sacrificial life as “reasonable service” in Romans 12:1:

  I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service. (NKJV)

Sacrifice, no matter how great, is reasonable because of what God did for us so that we might have forgiveness of our sins. This he did, not because of our goodness, but “while we were yet sinners” (Rom. 5:8). That is, his love was manifested by the sacrifice of his only begotten son while we were at enmity with him. Sacrifice on our part is also reasonable because of Jesus’ own sacrifice in lowering himself to take on the form of a man, only to die a death he didn’t deserve, for the sake of us who didn’t deserve his mercy. In leaving his home in heaven Jesus wasn’t getting a promotion. He wasn’t here on a sightseeing excursion; he was here on a mission.
Whenever we begin to fuss about any sacrifice our training for godliness requires, we need to remember the agony in the garden that produced sweat “like great drops of blood” (Luke 22:44). If we think we have it hard, we need to recall the taunting, the scourging and the crown of thorns on His brow (John 19:1, 2). When we think we’ve sacrificed enough, we must remember the weight of the cross He was called to carry (John 19:17). Whatever we do, let’s not forget the nails! Oddly enough, not one of the four gospel accounts, in describing the crucifixion, mentions Jesus’ hands and feet being nailed to the cross, but we know it took place. King David clearly prophesied it in Psalm 22:16–18:

  For dogs have surrounded Me; The assembly of the wicked has enclosed Me. They pierced My hands and My feet; I can count all My bones. They look and stare at Me. They divide My garments among them, And for My clothing they cast lots. (NKJV)

The apostle Thomas, not believing the eyewitness reports of Jesus’ resurrection, said: “Unless I see in His hands the print of the nails … I will not believe” (John 20:25). Eight days later, when Jesus next appeared to His disciples, Jesus singled Thomas out and said, “look at my hands … do not be unbelieving, but believing” (John 20:27). At seeing this Thomas believed, and Jesus invoked a blessing on “those who have not seen and yet believe” (John 20:29).
Though we have not seen with our eyes, we believe in the nailscarred hands! I cannot imagine any part of the crucifixion that was more of a sacrifice than Jesus submitting to having His hands and feet nailed to the cross. More than likely we will never have to have nails driven through our hands, but it’s entirely reasonable to expect us to be willing to make sacrifices in our lives as we discipline ourselves for the purpose of godliness. After all, as our Lord said: “A disciple is not above his teacher, nor a servant above his master” (Matt. 10:24).

Diestelkamp, A. (2009). Discipline Yourself for Godliness. In D. W. Petty (Ed.), Guard the Trust: Studies in Paul’s Letters to Timothy and Titus (pp. 227–228). Temple Terrace, FL: Florida College Bookstore.