The term "spiritual discernment" means the skill of separating divine truth from error. We gain this skill through God's grace and reading His word.
"And this is my prayer, that your love may overflow more and more with knowledge and full insight to help you to determine what is best, so that in the day of Christ you may be pure and blameless, having produced the harvest of righteousness that comes through Jesus Christ for the glory and praise of God." (Philippians 1:9–11)
In this passage from Philippians, Paul is praying for the church at Philippi. The central theme in the prayer is that the readers will exercise the virtue of spiritual discernment. Paul wants them to be able to make good choices, to “determine what is best.”
In doing so, Paul gives us the anatomy of this virtue. He points to three necessary building blocks for discernment: love, knowledge, and insight. And he describes the desired result of exercising this gift: the harvest of righteousness that will contribute to the glory and praise of God.
In the next passage, Paul is speaking to the church at Corinth. He points out that he and the other apostles spoke the truth from "the spirit that is from God, so that we may know the things that are freely given to us by God."
"For who among men knows the things of a man except the man’s spirit within him? So too, no one knows the things of God except the Spirit of God. Now we have not received the spirit of the world, but the Spirit who is from God, so that we may know the things that are freely given to us by God. And we speak about these things, not with words taught us by human wisdom, but with those taught by the Spirit, explaining spiritual things to spiritual people. The unbeliever does not receive the things of the Spirit of God, for they are foolishness to him. And he cannot understand them, because they are spiritually discerned. The one who is spiritual discerns all things, yet he himself is understood by no one. For who has known the mind of the Lord, so as to advise him? But we have the mind of Christ." (1 Corinthians 2:11-16)
Here, Paul contrasts the ability of the believer to that of the unbeliever to receive "the things of the Spirit of God."
Read and listen to Proverbs:
My child, if you receive my words,
and store up my commands within you,
by making your ear attentive to wisdom,
and by turning your heart to understanding,
indeed, if you call out for discernment –
raise your voice for understanding –
if you seek it like silver,
and search for it like hidden treasure,
then you will understand how to fear the Lord,
and you will discover knowledge about God. (Proverbs 2:1-5)
Obtaining spiritual discernment is not something that you can do once a week. It can only be gained by digging deeply into God's word.