Paul urgently entreats us to service because of the mercy and Grace of our Lord that we have received.
Furthermore, since the body is to be redeemed at our Lord`s appearing we ought to make the temporal body of flesh a sacrifice to His service.
The HolySpirit is the sanctifier 1Cor 6:11 and so our body of flesh is usable by Him.
We serve our LordJesusChrist by submitting to the lead of His HolySpirit in us.