Look, Christian, on thy Bible, and that glass
That sheds its sand through minutes, hours, and days,
And years; it speaks not, yet, methinks, it says,
To every human heart: so mortals pass
On to their dark and silent grave! Alas
For man! an exile upon earth he strays,
Weary, and wandering through benighted ways;
To-day in strength, to-morrow like the grass
That withers at his feet!--Lift up thy head,
Poor pilgrim, toiling in this vale of tears;
That book declares whose blood for thee was shed,
Who died to give thee life; and though thy years
Pass like a shade, pointing to thy death-bed,
Out of the deep thy cry an angel hears,
And by his guiding hand thy steps to heaven are led!

William Lisle Bowles

http://www.poemhunter.com/poem/hour-glass-and-bible/