A grammatical problem about a Germany Proverb

The Proverb is as the following sentence:

"Was du heute kannst besorgen, das verschiebe nicht auf morgen."

I learned it from a language website. But my German teacher thought it was a grammatical wrong sentence. Her idea of expression was as follows:

"Das, was du heute kannst besorgen, nicht auf morgen verschiebe!"

She put it as a imperative. I'm confused.

Please help me! Thank you :)

Hilfe mir bitte! Vielen Dank!