"What a teacher writes on the blackboard of life can…

“What a teacher writes on the blackboard of life can never be erased” is a saying that has been printed on many images, usually showing the saying in chalk on a blackboard. The saying has been cited in print since at least 2009 and is of unknown authorship.

Educators—Know the Ropes
02 September, 2009
Happy Teacher’s Day
(...)
What a teacher writes on the blackboard of life can never be erased!

Twitter
Isabella
‏@Bella_Sunn
“What a Teacher writes on the blackboard of life can never be erased.” ~Unknown
10:25 PM - 4 Nov 2010

Google Books
A Tribute to Teachers: Wit and Wisdom, Information and Inspiration about Those Who Change Our Lives
By Richard Lederer
Portland, OR: Marion Street Press
2011
Pg. ?:
What a Teacher Writes on the Blackboard Of Life Can Never Be Erased.

Twitter
♛ Dewi Batrishya ♛
‏@DewiBatrishya
What a teacher writes on the blackboard of LIFE can Never be erased… 😊
6:06 AM - 9 Sep 2011

Google Books
Chicken Soup for the Soul: The Magic of Mothers & Daughters:
101 Inspirational and Entertaining Stories about That Special Bond
By Jack Canfield, Mark Victor Hansen and Amy Newmark
New York, NY: Simon & Schuster
2012
Pg. ?:
What a teacher writes on the blackboard of life can never be erased. ~Author Unknown

Google Groups: Sanborn Central e-News
[Sanborn Central e-News] November 15, 2012
Blogger
11/15/12
SANBORN CENTRAL E-NEWS
Today is Teacher Day for National Education Week. Sanborn Central is very fortunate to have the quality of caring educators that we do. A person doesn’t realize until after they’ve graduated what a big impact teachers have on them. “What a teacher writes on the blackboard of life can never be erased. – Author Unknown”

Vanguard (Nigeria)
Utuk, `super teacher’, at 80, receives his reward
on October 03, 2015 / in News 10:01 pm
By Sam Akpe
(...)
A good teacher fulfils the old saying that “what a teacher writes on the blackboard of life can never be erased.”