Your 'Vessel'
is,

You...
Your actions, your mind,
your body, your soul.
Doing right, abiding in the Spirit, and
not giving in to sin, helps you to,
"...possess your vessel
in sanctification
and honour...".

For this is the will of God,
even your sanctification,
that you should abstain from fornication;
that every one of you should know
how to possess his vessel
in sanctification and honour;
not in the lust of concupiscence,
even as the Gentiles which know not God.

1 Thessalonians 4:3-5