Spiritual life is walking after the spirit by the Spirit, focused on the spirit, exercising and strengthening our spirit, substantiating things unseen. Such is the life, in Christ Jesus, the only help that could ever work, authentically, for us helpless sinners in achieving victorious life: with Christ, Christ in me, and for Christ.
Victorious life can not be reached without receiving His substitutionary death on the cross and entering co-death (identification) with Christ. Having died with Jesus on the cross (unto power over sin), now we determine to bear our cross in daily experience (power over the soul life) to deny ourselves and taking up our cross (forsaking the world). Every cross that passes before us beckons us to forsake ourselves, these being a daily affair until our natural independence is lost and overcome step by step. Jesus told his disciples, "If any man would come after me, let him deny himself and take up his cross and follow me" (Matt. 16.24).
The deeper the Word of God penetrates (Heb. 4.12), the deeper the work of the cross and the further the Holy Spirit completes the union of life of our spirit with the Lord Jesus. To deny ourselves and that part of the soul that still remains exalted, we must recognize that part exists to be able to lay bare more of its natural life and allow the cross to probe deeper and deeper. This is why the cross is borne daily.
God knows the true condition of the soul life. After Peter declares Jesus is Lord, immediately his flesh rises up to forsake the cross that Jesus must bear by imploring the Lord to pity himself. This shows that to worship the Lord by soul power is of no effect. Unless the natural realm has been treated drastically by the cross it shall continue to be preserved in man. Self-preservation of the soul is its prime motivation of self-pity, self-love, fear of suffering and withdrawal from the cross.
"And he said unto all, If any man would come after me, let him deny himself, and take up his cross daily, and follow me" (Luke 9.23).
In Romans 6-7, there is mention of the "law of sin" that energizes us to do things against God; leads to the "law of death", incapable of doing this for God. The flesh (sin of the body and self of the soul) must die completely on the cross. It can not be changed, refined or beautified. It must die so that we can live. There is no other way. Vanity is not an option. The self-life must utterly be put to naught. It is an accomplished fact we have already died in Christ with Him at Calvary.
Now may that union be accomplished to deny self again so that what is not contained by death, may rise up in resurrection life until eventually there is nothing left which needs to die. Having once died, we put to death fully the deeds of the flesh-sin of the body and self of the soul. What is accomplished in the former (our death with Christ), provides for the power to do the latter (put to death).
"Beloved, think it not strange concerning the fiery trial which is to try you, as though some strange thing happened unto you: But rejoice, inasmuch as ye are partakers of Christ's sufferings; that, when his glory shall be revealed, ye may be glad also with exceeding joy" (1 Pet. 4.12,13).
Praise the Lord for God Himself and His righteousnss (His way of doing things) and His holiness (His nature)!