Quote from ACIM Text Chapter 4, Section 8 - Creation and Communication.

God has kept your kingdom for you, but he cannot share his joy with you until you know it with your whole mind. Revelation is not enough, because it is only communication from God. God does not need revelation returned to him, which would clearly be impossible, but he does want it brought to others. This cannot be done with the actual revelation; its content cannot be expressed, because it is intensely personal to the mind that receives it. It can, however, be returned by that mind to other minds, through the attitudes the knowledge from the revelation brings.