Robert Louis Stevenson

What man may learn, what man may do,
Of right or wrong of false or true,
While, skipper-like, his course he steers
Through nine and twenty mingled years,
Half misconceived and half forgot,
So much I know and practise not.

Old are the words of wisdom, old
The counsels of the wise and bold:
To close the ears, to check the tongue,
To keep the pining spirit young;
To act the right, to say the true,
And to be kind whate'er you do.

Thus we across the modern stage
Follow the wise of every age;
And, as oaks grow and rivers run
Unchanged in the unchanging sun,
So the eternal march of man
Goes forth on an eternal plan.