Get out the microscope, because we’re going through this poem line-by-line.
Of ages glide away, the sons of men,
- We’re pretty sure you’ve got the idea by now, but the speaker is headed for his big conclusion, so we’re not about to stop him. We’re going to get one last survey of the history of humanity ("the long train / of ages"). As that history "glides away," all the "sons of men" pass away too.
The youth in life’s green spring, and he who goes
In the full strength of years, matron and maid,
The speechless babe, and the gray-headed man—
- Once more: everyone dies. Young people, in the "green spring" of life, will eventually die.
- People in the prime ("full strength") of life will die too.
- The old woman ("matron") will die, but so will the young woman ("maid").
- The same goes for babies who are too young to talk and old men with grey hair.
- Death is the great equalizer. Doesn’t matter who or when or what you are – you will die.
Shall one by one be gathered to thy side,
By those, who in their turn shall follow them.
- All the people listed in lines 68-70 are going to come and lie down next to you in the earth. They will be laid in the grave by people who will then eventually die themselves. It’s an endless chain, all of us following each other into the grave, whether we like it or not.