'Write to Sardis,' saith the Lord,
'And write what He declares,
He whose Spirit, and whose word,
Upholds the seven stars:
All thy works and ways I search,
Find thy zeal and love decay'd;
Thou art call'd a living church,
But thou art cold and dead.

'Watch, remember, seek, and strive,
Exert thy former pains;
Let thy timely care revive,
And strengthen what remains;
Cleanse thine heart, thy works amend,
Former times to mind recall,
Lest my sudden stroke descend,
And smite thee once for all.

'Yet I number now in thee
A few that are upright;
These my Father's face shall see,
And walk with me in white.
When in judgment I appear,
They for mine shall be confess'd;
Let my faithful servants hear, -
And woe be to the rest!'

William Cowper

http://www.poemhunter.com/poem/olney-hymn-21-sardis/