What did Christ say concerning secret prayer?

Answer

"But thou, when thou prays, enter into thy closet, and when thou has shut thy door, pray to thy Father
which is in secret; and thy Father which sees in secret shall reward thee openly." Matt. 6: 6.

Because of this, what is Christ able to do?
Is there a specified time for the cleansing of the heavenly sanctuary?
How will the decisions of the judgment be executed?
What is to endure throughout all generations?
Why was the gospel to be preached to the Gentiles?
How will this great event affect the world?
But are not the righteous dead in heaven?

Questions & Answers are from the book Bible Readings for the Home Circle