We are not our own: let not our reason nor our will, therefore, sway our plans and deeds. We are not our own: let us therefore not set it as our goal to seek what is expedient for us according to the flesh. We are not our own: in so far as we can, let us therefore forget ourselves and all that is ours. Conversely, we are God's: let us therefore live for him and die for him. We are God's: let his wisdom and will therefore rule all our actions. We are God's: let all the parts of our life accordingly strive toward him as our only lawful goal.
Self-denial is not denying to ourselves luxuries such as chocolates, cakes, cigarettes and cocktails (although it might include this); it is actually denying or disowning ourselves, renouncing our supposed right to go our own way.