Hardly anything mechanical in this whole World can do without some kind of oil or lubrication. Where moving parts rub together, they create friction. Friction creates heat, and heat creates fire and fire causes parts of the machine to burn up, consume! But oil that's poured on squeaky parts of a mechanism that are complaining and howling and growling and groaning makes that part of the mechanism quiet and run smoothly without complaint!
Our spirits, like machinery, need cleaning and oiling--the washing of the pure water of the Word and the oiling of the Love and patience of the Holy Spirit! If we didn't have the Oil of the Holy Spirit we would get rusty and break down or overheat from friction, slow down or stop! Without proper maintenance and lubrication, there would soon be no useful motion and we'd be fit only for God's junk pile!
But thank God, the Oil of His Holy Spirit oils everything: Our heads, our hearts, our spirits, our tongues and even our feet so we'll go and preach the Gospel! He just pours in the Holy Spirit and just fills us from top to bottom and covers every part! Thank You Jesus! (Acts 2:17,18)