Shortly after Ronnie Van Zant's grandmother and Gary Rossington's mother died, they got together in Van Zant's apartment and started telling stories about them. Rossington came up with a chord progression, and Van Zant wrote the lyrics based on advice the women had given them over the years. They wrote it in about an hour.
Even though the lyrics state, "Sit beside me, my only son," Ronnie was not the only son. He had 2 younger brothers along with one older sister and one younger sister.
This appears on the soundtrack to the movie Almost Famous.
Skynyrd producer Al Kooper didn't like the way this was coming out, so the band recorded it without him and had him add his organ part later. He didn't think they should release it, but realized he was wrong when it went over so well with their fans.
When Skynyrd toured in 1987, they dedicated this to Van Zant.

Lyrics
Mama told me when I was young
"Come sit beside me, my only son
And listen closely to what I say
And if you do this it'll help you some sunny day"
"Oh, take your time, don't live too fast
Troubles will come and they will pass
You'll find a woman and you'll find love
And don't forget, son, there is someone up above"
"And be a simple kind of man
Be something you love and understand
Baby, be a simple kind of man
Oh, won't you do this for me, son, if you can"
"Forget your lust for the rich man's gold
All that you need is in your soul
And you can do this, oh baby, if you try
All that I want for you, my son, is to be satisfied"
"And be a simple kind of man
Oh, be something you love and understand
Baby, be a simple kind of man
Oh, won't you do this for me, son, if you can"
Oh, yes, I will
"Boy, don't you worry, you'll find yourself
Follow your heart and nothing else
And you can do this, oh baby, if you try
All that I want for you, my son, is to be satisfied"
"And be a simple kind of man
Oh, be something you love and understand
Baby, be a simple kind of man
Oh, won't you do this for me, son, if you can?"
"Baby, be a simple, be a simple man
Oh, be something you love and understand
Baby, be a simple kind of simple man
Oh, won't you do this for me, son, if you can?"