I love that verse. You see, as a teacher, I have the skewed perspective that if I will just give people enough information—if I will teach them adequately—then they’ll get it. They will understand and act on what I’ve said. If I do my job well then they will comprehend the message and it will make a difference.
Yet such a perspective leaves God out of the equation. And He is absolutely essential to that equation. Without Him, it really doesn’t work at all.
So rather than just stand in front of people and expound on the immense amount of knowledge I have gained over the years, I first need to ask the Lord to open “their minds to understand the Scriptures.” If He doesn’t do that, then all my eloquent words will not have the necessary impact.
I would suggest that, in like manner, when you share the gospel with someone, the majority of your effort needs to be in praying for the hearer. If God doesn’t open the mind of the person to receive the words, then the impact will be minimized.
People can close their minds, but only the Lord has the key that can truly open them.