Self-denial is a Christian virtue, granted by God to His children, whereby they, out of love for God’s will, neither give heed nor yield to their intellect, will, and inclinations insofar as they are in opposition to the will of God – and oppose and suppress them instead. They do so by a voluntary forsaking and rejection of all that pertains to their natural well-being, if God’s cause demands such from them – this (is) to the honor of God and the welfare of their neighbors.

Self-denial is, first, a Christian virtue⤒🔗

Pagans have observed that their inner peace has been disturbed by their lusts. Some therefore sought to extinguish them by way of reason and appeared to practice self-denial regarding some things. How­ever, it did not issue forth from the right motive – love for the will of God. They did not have the right objective in view, but rather it was a seeking of self (be it in a different manner from others), resting in this as their peace and seeking to be honored by men. Their self-denial was thus a splendid sin that had a counterfeit luster and was not accompanied by deeds.

Our reference here, however, is to the self-denial of a Christian as being exclusive of all inordinate self-love (and self-reliance that issues forth from this) and seeking of self. Such self-denial issues forth from love for the will of God and culminates in the glorification of God.   

Second, the moving cause of self-denial is the Lord and not man himself←⤒🔗

Man is too deeply immersed in self-love to be able to rid himself from it. Even if he could divorce himself from this, he would not be able to bring himself into the oppo­site virtuous disposition. Self-denial does not consist in a negation, but is rather a propensity. The Lord grants this grace to His children, for He grants them spiritual life in regeneration (Eph. 2:1; James 1:18). Through this virtuous disposition, He causes them to be active and thus works in them to will and to do (Phil. 2:13). He particularly works in them the mortification of sin:

but if ye through the Spirit do mortify the deeds of the body, ye shall live.Rom. 8:1

God, having given life in the soul, stirs up this life and ren­ders it active by His prevening¹ and cooperative power. The believer – uniting himself by faith with Christ and through Christ with God – takes hold of His strength as his own. By reason of this received strength, he is active in mortifying sin within him. God is thus the original cause: man, having been affected by this power, is himself active in the casting out of sinful self-love and its consequences, as well as in purify­ing and adorning himself with the contrary virtue. “Let us cleanse ourselves” (2 Cor. 7:1); “work out your own salvation with fear and trembling. For it is God which worketh in you both to will and to do of his good pleasure” (Phil. 2:12-13).

Third, the subjects of self-denial are the children of God←⤒🔗

The unconverted are void of all spiritual life; therefore, the motions and operation of life cannot come forth from them. Rather, it is a gift to God’s children as presently being in a converted and believing state. They are those who are Christ’s disciples and follow Him (Matt. 16:24). Self-denial does not consist in a few deeds, but is rather a propensity and disposition of the heart. Their heart has been turned away from self-love and a seeking of self – albeit imperfectly ... Once this virtue has become deeply rooted, the person who practices self-denial will have much inner peace. He will not so readily be enticed to entertain ulterior motives or be envious, wrathful, and guilty of misuse of words – all of which frequently issue forth in a rash manner due to self-love and a seeking of self ... All that he does renders him pleasant to all – before God and before men.

Fourth, the object of self-denial is man himself←⤒🔗

God has created self-love in man and mandates the exercise of this love in the Second Table of the Law by giving command that we are to love our neighbor as ourselves (Matt. 22:39). After the fall, however, love has become entirely distorted, as it causes man to be opposed to God, to make himself as God, and wanting all to end in man. This principle governs fallen man in his operations, and he wants everyone to function toward him in harmony with this principle.