We cannot count our friends, nor say
How many praise us day by day.
Each one of us has friends that he
Has yet to meet and really know,
Who guard him, wheresoe'er they be,
From harm and slander's cruel blow.
They help to light our path with cheer,
Although they pass as strangers here.

These friends, unseen, unheard, unknown,
Our lasting gratitude should own.
They serve us in a thousand ways
Where we perhaps should friendless be;
They tell our worth and speak our praise
And for their service ask no fee;
They choose to be our friends, although
We have not learned to call them so.

We cannot guess how large the debt
We owe to friends we have not met.
We only know, from day to day,
That we discover here and there
How one has tried to smooth our way,
And ease our heavy load of care,
Then passed along and left behind
His friendly gift for us to find.

Edgar Albert Guest

http://www.poemhunter.com/poem/the-unknown-friends/