This is spiritual discernment. Discernment is the ability to distinguish between the chaff and wheat, the dross and the gold, the genuine and the superficial. Automobiles need to be tested on a torture track before they are sold to the public. If a car's breaks do not meet the test they are sent back for redesign. You do not put a car with faulty breaks on the market.
Lives are at stake.
In order to test those breaks some standard for testing needs to be applied. A standard or measure for what is good breaks is needed. God wants us to test for approval, have a criterion for whatever comes into our lives. If we have this criterion we can resolve the priorities of our life. Any problem or set of alternatives which is set before us should be measured by this standard.