Have you ever taken a test without studying? Did you ask God for help, knowing you’re not going to remember what you didn’t know in the first place?
Now, there are some who do well without studying much (or not at all), but that’s mostly due to good test-taking skills, rather than possessing actual knowledge of the given subject. An ‘educated’ guess is still a guess.
While serving in the US Air Force, I spent three months working security for refugee camps at the US Naval Base, Guantanamo Bay, Cuba. Because much of our day was inactive, I spent several hours studying for promotion, alternating between that and reading the Scripture.
One day while studying, a fellow Airman picked up my Bible, opened it to a random page, and asked, “Who was the son of Hagar?” When I immediately answered, “Ishmael”, he quickly put the Bible back on the desk in frustration and walked away.
This didn’t happen to make me look good, but to the glory of God! I could never have known what question he was going to ask, but the Holy Spirit brought it to my ‘remembrance’ exactly on time. I didn’t need to commit to memory every word of the Bible, but because I studied the Scripture often, God used me to ensure His Word would do its work.