Years ago I read “Point Man” by Roger Helle. He described how the point man went ahead of his platoon to check for concealed landmines. It took experienced discernment to detect any nuance of changes on the ground. For instance leaves that were in an unnatural pattern.
Hebrews 5:14 says, “…those who by reason of use have their senses exercised to discern both good and evil.” The Greek words used indicated discrimination, constant use, habit, practice, perception, and judgment.
1 John 1:6 says, “If we say that we have fellowship with Hm, and walk in darkness, we lie and do not practice the truth.” As we practice truth, we learn to discern. Discerning takes attentiveness, being alert, and watchful. They are all action words. We don’t discern by osmosis. Walking in the Spirit teaches us to pay attention to every nuance.
Luke 4:4 Amplified says, “…Man shall not live by bread alone, but by every word and expression of God.” 1 Corinthians 12:10 says that discerning of spirits is a manifestation of the Spirit. That means it is given by the Holy Spirit.