Acts 7 verse 30 "And when forty years were expired, there appeared to him in the wilderness of mount Si-na an angel of the LORD in a flame of fire in a bush."
I remember entering high school in 1966. I knew if I completed all the work, I would graduate in 1970, and have my high school diploma. I did graduate and then went on to college for awhile, joined the Army, but still pursued my college degree while serving on active duty. Finally, 13 years after I graduated from high school, I had my college degree. During the same timeframe, I graduated from many military courses. This education enabled me to better perform my work, and equipped me for other work that I would later do. I sure was glad to graduate!
The Lord had Moses in training school for 40 years. He was on the back side of the wilderness, a day like any other day, when the Lord appeared unto him, gave him his "graduation" papers, and told him about the mission he was to perform. Moses had learned much in "school", and was the most humble man living. Although he didn't think that he was capable of performing such an awesome task as leading the Israelites out of Egypt's bondage, God knew he could because He had trained him. I sometimes wonder what kind of diploma Moses would have. Maybe a PHD in wilderness experience. I imagine Moses spent many lonely days questioning his existence, and his state of life. After all, he had grown up in a Pharaoh's house...he went from riches to middle class living (would be the equivalent of someone today moving from the White House to a double wide trailer).
All throughout the Bible, there have been those who have come to their "graduation" day. The Lord had them in His classes, taught them valuable lessons, and when He knew the time was right, He issued them their "diplomas". Remember Joseph, the man sent by the Lord to Egypt so that all of Israel could be saved during a famine? Many years expired while Joseph was learning his lessons. Then that one morning he woke up in prison, "graduated" that day, and became second in charge of the whole land of Egypt!
Many present time children of God are in training as He is preparing them for such a time as this. When the lessons are over, the last test is passed, the Lord will issue "graduation" papers, and the mission they were trained for will be fulfilled!
Psalm 105 verse 19 "Until the time that his word came: the word of the LORD tried him."