Establishing Heaven on Earth

We must do what is possible to establish Heaven on Earth.

According to the  book A Course In Miracles (ACIM), we are already in Heaven. ACIM states this in the section Is Reincarnation Real in The Manual for Teachers.

Do what you can to help establish Heaven on Earth and in this Universe.

Always stay in Heaven if possible. Do not leave Heaven.

All that is not part of Heaven is ultimately illusions.