When this song came out it just didn't seem like this was a song Glen Campbell would have written. Turns out, it is a poem from 1909 by Edgar A. Guest. He called it "A Creed," a title he evidently used for several of his poems.

Here is the text from an online site. Not identical but clearly the source.

A Creed
Let me be a little kinder,
Let me be a little blinder
To the faults of those around me,
Let me praise a little more;
Let me be, when I am weary
Just a little bit more cheery,
Let me serve a little better
Those that I am striving for.

Let me be a little braver
When temptation bids me waver,
Let me strive a little harder
To be all that I should be;
Let me be a little meeker
With the brother that is weaker,
Let me think more of my neighbor
And a little less of me.

Let me be a little sweeter,
Make my life a bit completer
By doing what I should do
Every minute of the day;
Let me toil, without complaining,
Not a humble task disdaining,
Let me face the summons calmly
When death beckons me away.