Jesus, the assurance of prayer!

40 Jesus saith unto her, Said I not unto thee, that, if thou wouldest believe, thou shouldest see the glory of God? 41 Then they took away the stone from the place where the dead was laid. And Jesus lifted up his eyes, and said, Father, I thank thee that thou hast heard me. 42 And I knew that thou hearest me always: but because of the people which stand by I said it, that they may believe that thou hast sent me (John 11:40-42 KJV)