Romans 8:11 — But if the Spirit of Him that raised up Jesus from the dead dwell in you, He that raised up Christ from the dead shall also quicken your mortal bodies by His Spirit that dwelleth in you.
from the dead — from among the dead
Jesus — one of only two places (the other is 3:26) where the single name is used. Here it is used as the One who is a pledge of all that is secured in Him for believers.
quicken = The reference is not to the impartation of some special energy of life and power to our bodies in the present state, but to the effect upon them of the shout of the Lord at the time of the Rapture (see Romans 7:24; 1 Thessalonians 4:17; Philippians 3:20-21; 1 Corinthians 15:52-53). — W.E. Vine, The Epistle to the Romans, page 117.
by His Spirit — should be "because of His Spirit."
Scripture does not speak of the Holy Spirit as the One who will raise the dead and change the living saints. He is not the means but the cause … The power that wrought in Christ is the power that will accomplish the quickening of our death-doomed bodies (Ephesians 1:18-20). — The Epistle to the Romans, page 117.
The quickening is now. The Spirit is now enabling us to overcome the flesh — therefore verse 12.