11. But--"And."
      if the Spirit of him that raised up Jesus from the dead dwell in you--that is, "If He dwell in you as the Spirit of the Christ-raising One," or, "in all the resurrection-power which He put forth in raising Jesus."
      he that raised up Christ from the dead--Observe the change of name from Jesus, as the historical Individual whom God raised from the dead, to CHRIST, the same Individual, considered as the Lord and Head of all His members, or of redeemed Humanity [ALFORD].
      shall also quicken--rather, "shall quicken even"
      your mortal bodies by--the true reading appears to be "by reason of."
      his Spirit that dwelleth in you--"Your bodies indeed are not exempt from the death which sin brought in; but your spirits even now have in them an undying life, and if the Spirit of Him that raised up Jesus from the dead dwell in you, even these bodies of yours, though they yield to the last enemy and the dust of them return to the dust as it was, shall yet experience the same resurrection as that of their living Head, in virtue of the indwelling of same Spirit in you that quickened Him."

JFB.