Eph 3:14-16, 14 For this reason I bow my knees to the Father of our Lord Jesus Christ, 15 …, 16 that He would grant you, according to the riches of His glory, to be strengthened with might through His Spirit in the inner man.
The revelation of the mystery leads the apostle to once more pray for believers. I realize that this prayer concurs with Psalm 25 where David prays to be shown, be taught and be led. The prayer is for the Holy Spirit to do a continuous work of revelation and sanctification with the focus on the preservation of the inner man.
The oil’s principal purpose in an engine is to scale back friction and the decline of the moving elements, cleaning it up. The preservation oil is to give protection against corrosion. Paul is praying that believers would be oiled, reinforced and preserved to stay robust in each state of their walk.
The outer man is getting old and perishing, the inner man, the new creation is being renewed and preserved day by day until that day. 2Co 4:16 “Therefore we do not lose heart. Even though our outward man is perishing, yet the inward man is being renewed day by day.”
God daily supplies what we need for our keeping and preservation. Psa 68:19 ”Blessed be the Lord, Who daily loads us with benefits,…”