1 Nephi 10:17-19 Doctrine and Covenants 11:21-22 Doctrine and Covenants 50:19-24 Doctrine and Covenants 88:118
In many churches, the mysteries of God are considered unknowable by man. In our church, this is not the case. A mystery is any doctrine or principal that you do not yet understand. Heavenly Father doesn't want to withhold information from us. He wants us to learn always. That is why we have the scriptures; that is why He has commanded us to study them, no not just to study them, but to FEAST upon the scriptures. He wants us to be hungry for the knowledge, the mysteries contained in them, and He promises to fill us according to our desires.
There is a caveat, however. Gospel knowledge is given "line upon line, precept upon precept." (Isaiah 28:10, 13; 2 Nephi 28:30) You cannot expect to receive revelation about all the worlds created if you haven't yet developed the faith to pray. You cannot expect to understand the atonement if you don't have the faith to repent. Heavenly Father has promised to give us milk before meat. (1 Corinthians 3:2) Don't ask for something you're going to choke on.
And that is the beauty of reading the scriptures over and over again. I approach the scriptures each time with different needs and a different level of understanding. It becomes a personal conversation, as the Lord reveals to me exactly what I need exactly when I need it, to lead me towards personal growth, comfort, and knowledge. And always, the scriptures lead me to Christ, they lead me to act, and they lead me to become a better person.