Satan can occasionally work miracles, as we see with Pharaoh’s sorcerers (Ex. 7:11), and as Jesus warns concerning false Christs and false prophets (Matt. 24:24). But Satan cannot produce virtues. He is incapable of producing joy, peace, goodness, kindness, love for Christ, love for God, love for the Holy Spirit, love for the Scripture, love for truth. Only Christ produces these things. Therefore, such fruit testifies to the genuine work of Christ.
Does it miss the point? Mormons can claim to display the fruit of the Spirit. You need a stronger confessional guardrail, as Jesus goes on yo give in the next verses of Matthew 7. There he says that you must know him even if you display great works and call him Lord.
