[What3ver]

Grateful as you already have it - even though you know it has not manifested YET, a master knows and has the faith that it certainly WILL BE and so is grateful in advance. Because being grateful in advance is the key to manifesting it. Conversations with God(book 1). Not quoted.

edit: from the book

5.All creation begins with thought (“Proceeds from the Father”). All creation then moves to word (“Ask and you shall receive, speak and it shall be done unto you”). All creation is fulfilled in deed (“And the Word was made flesh, and dwelt among us”).

6.That which you think of, but thereafter never speak of, creates at one level. That which you think of and speak of creates at another level. That which you think, speak, and do becomes made manifest in your reality.

7.To think, speak, and do something which you do not truly believe is impossible. Therefore, the process of creation must include belief, or knowing. This is absolute faith. This is
beyond hoping. This is knowing of a certainty (“By your faith shall ye be healed”). Therefore, the doing part of creation always includes knowing. It is a gut-level clarity, a total certainty, a complete
acceptance as reality of something.

8.This place of knowing is a place of intense and incredible gratitude. It is a thankfulness in advance. And that, perhaps, is the biggest key to creation: to be grateful
before, and for, the creation. Such taking for granted is not only condoned, but encouraged. It is the sure sign of mastery. All Masters know in advance that the deed has been done.