Discernment is “the skill of understanding and applying God’s Word with the purpose of separating truth from error and right from wrong” (Tim Challies).
If the above definition is true (and I think it is), where should discernment start? I propose that it starts with how one thinks of God. A. W. Tozer wrote in The Knowledge of the Holy, “What comes into our minds when we think about God is the most important thing about us.” He goes on to say,
For this reason the gravest question before the Church is always God Himself, and the most portentous fact about any man is not what he at any given time may so or do, but what he in his deep heart conceives God to be like. . . .Were we able to extract from any man a complete answer to the question, “What comes into your mind when you think about God?” we might predict with certainty the spiritual future of that man. Without doubt, the mightiest thought the mind can entertain is the thought of God, and the weightest word in any language is its word for God.
Trace any error in doctrine or religion and you will see that it began with some wrong view of God. Our thoughts about God shape everything else.
So discernment starts with your view of God. This is discernment 101. If you want to be able to discern between truth and error, you have to make sure you know God or else, in the words of J. I. Packer, “you sentences yourself to stumble and blunder through life blindfolded, as it were, with no sense of direction and no understanding of what surrounds you. This way you can waste your life and lose your soul.”