11 Concerning him we have much to say, and it is hard to explain, since you have become dull of hearing. 12 For though by this time you ought to be teachers, you have need again for someone to teach you the elementary principles of the oracles of God, and you have come to need milk and not solid food. 13 For everyone who partakes only of milk is not accustomed to the word of righteousness, for he is an infant. 14 But solid food is for the mature, who because of practice have their senses trained to discern good and evil. Hebrews 5:11-14 (NASB)
A couple of decades ago, I was sent to training by the bank I was working for. It was a Microsoft NT Networking class. The teacher was great. I learned many new skills and honed old ones. I became part of the network rollout team after I came back from training. One of the things the teacher taught us was how to get under the covers of the operating system. He called it looking under the hood. He made it clear it was impossible to do proper diagnostics without digging into what was happening under the covers.