Union with Christ

Here's a prayer titled "Union with Christ" from "Valley of Vision: A collection of Puritan Prayers & Devotions" edited by Arthur Bennett (pages 36-37):

O FATHER,

Thou hast made man for the glory of thyself,
and when not an instrument of that glory,
he is a thing of nought;

No sin is greater than the sin of unbelief,
for if union with Christ is the greatest good,
unbelief is the greatest sin,
as being cross to thy command;
I see that whatever my sin is,
yet no sin is like disunion from Christ by unbelief.

Lord, keep me from committing the greatest sin
in departing from him,
for I can never in this life perfectly obey
and cleave to Christ.

When thou takest away my outward blessings,
it is for sin,
in not acknowledging that all that I have is of thee,
in not serving thee through what I have,
in making myself secure and hardened.

Lawful blessings are the secret idols, and
do most hurt;
the greatest injury is in the having,
the greatest good in the taking away.

In love divest me of blessings that I may glorify
thee more;
remove the fuel of my sin,
and may I prize the gain of a little holiness
as overbalancing all my losses.

The more I love thee with a truly gracious love
the more I desire to love thee,
and the more miserable I am at my want of love;
The more I hunger and thirst after thee,
the more I faint and fail in finding thee,
The more my heart is broken for sin,
the more I pray it may be far more broken.

My great evil is that I do not remember
the sins of my youth,
nay, the sins of one day I forget the next.
Keep me from all things that turn to unbelief
or lack of felt union with Christ.