Bodhidharma was a Buddhist monk who lived during the 5th/6th century and is traditionally credited as the transmitter of Zen to China.
When delusions are absent, the mind is the land of Buddhas. When delusions are present, the mind is hell. Mortals create delusions. And by using the mind to give birth to mind they always find themselves in hell. Bodhisattvas see through delusions. And by not using the mind to give birth to mind they always find themselves in the land of Buddhas. If you don't use your mind to create mind, every state of mind is empty and every thought is still. You go from one Buddha-land to another. If you use your mind to create mind, every state of mind is disturbed and every thought is in motion. You go from one hell to the next. - Bodhidharma
If you use your mind to study reality, you won't understand either your mind or reality. If you study reality without using your mind, you'll understand both. . . . The mind and the world are opposites, and vision arises where they meet. When your mind doesn't stir inside, the world doesn't arise outside. When the world and the mind are both transparent, this is true vision. And such understanding is true understanding. - Bodhidharma
… the fools of this world prefer to look for sages far away. They don't believe that the wisdom of their own mind is the sage … the sutras say, "Mind is the teaching." But people of no understanding don't believe in their own mind or that by understanding this teaching they can become a sage. They prefer to look for distant knowledge and long for things in space, Buddha-images, light, incense, and colors. They fall prey to falsehood and lose their minds to insanity. - Bodhidharma
The Buddha is your real body, your original mind. This mind has no form or characteristics, no cause or effect, no tendons or bones. It's like space. You can't hold it. It's not the mind of materialists or nihilists. - Bodhidharma
Whoever knows that the mind is a fiction and void of anything real knows that his own mind neither exists nor doesn’t exist. - Bodhidharma
Everything good and bad comes from your own mind. - Bodhidharma
Source: The Zen Teaching of Bodhidharma