Quote from A Course in Miracles Text Chapter 19 - THE ATTAINMENT OF PEACE.

T-19.I.16. Let, then, your dedication be to the eternal, and learn how not to interfere with it and make it slave to time. 2 For what you think you do to the eternal you do to you. 3 Whom God created as His Son is slave to nothing, being lord of all, along with his Creator. 4 You can enslave a body, but an idea is free, incapable of being kept in prison or limited in any way except by the mind that thought it. 5 For it remains joined to its source, which is its jailer or its liberator, according to which it chooses as its purpose for itself.