Prayer Initiates Personal Revelation

Shortly after Oliver Cowdery began his labors as scribe while the Prophet Joseph Smith translated the engravings on the gold plates into the Book of Mormon, Oliver wanted a witness from God that the translation was true and that Joseph was a true prophet. Oliver had already received an answer to prayer about the authenticity of the plates and Joseph's mission before he had met the young prophet. Now that he was fully engaged in the work, however, Oliver wanted more divine reassurance. Joseph inquired of the Lord through the Urim and Thummim and received an answer. Jesus Christ, speaking through Joseph, gave Oliver the following promise:

And if thou wilt inquire, thou shalt know mysteries which are great and marvelous; therefore thou shalt exercise thy gift, that thou mayest find out mysteries, that thou mayest bring many to the knowledge of the truth, yea, convince them of the error of their ways.
--Doctrine and Covenants 6:11

God is willing to reveal great and marvelous truths to His children. He is not trying to hide anything from anyone. God does not work in secret. To initiate the revelatory process, however, we must inquire of the Lord. In other words, I must ask a question before God gives an answer. If I don't ask, He doesn't speak. God's mysteries don't have to remain mysteries to me, provided I really want to know something. 

I am aware, however, that God is economical. He won't reveal something to me that He has already revealed to ancient or modern prophets and they have written it down for me to study. I must do my homework. If I get to the end of the road in my study and find the answer has not yet been revealed, and if it's important to my salvation for me to know, God will reveal the knowledge I need. But only if I first ask. If I do not invite revelation, God will not force His knowledge upon me.