1 John 4:1 says to test the spirits whether they are of God. We are living in the end times where there is so much truth being mixed with error and saints of God are falling into it. This is why we need to exercise discernment.
Hebrews 5:14 says that the Mature are those who have exercised or trained their senses to discern between Good from evil.
This teaching is part of the series called “Principles Of Spiritual Warfare” and provides an understanding on the importance of discerning situations correctly so that good decisions are made that will be a blessing. Bad decisions are made from improper discernment.