Classic Poem

I' VE heard it said, and true is the remark,
That till thrice ten years o'er our beings steal,
We think we are immortal: that the spark
Within us, not like flash from smitten steel
Which instantaneous darkness doth conceal,
Is inextinguishable: yes, 'tis true,
Till we experimentally do feel,
By some home thrust, how easy to subdue
Life, it eternal seems to our fallacious view.