Since God created us to do His will, then it is logical to assume that God will not hide His will from us. He wants us to know His will.
How do we discover God's will?
We discover God's will by studying His word. The combination of the Bible and the Holy Spirit allow us to know and do God's will.
This is the point Henry and Richard Blackaby make in the book Hearing God’s Voice:
Many people underestimate God’s Word. It is far more powerful than many realize. From Genesis to Revelation God’s Word has the power to speak directly to a person’s heart. By the Holy Spirit, God takes his written Word and applies it specifically to people’s lives...The Bible is not merely one option for discovering God’s will. God’s written Word is the plumb line for our lives as we walk daily with him (p. 91).
If we hope to discover God’s will then the starting point needs to be the Bible. The Bible is God's revealed word to us, and the Holy Spirit is our divine teacher who helps us understand how God's will applies to our lives.
Finish reading at Paul's Ponderings: Commit to Know God's Will