When the Spirit of God controls us and we are walking in His power, we will prove it by the way we love the Lord and others.
Galatians 5:22-23 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, meekness, temperance: against such there is no law.
Many years ago, Dr. Donald Gray Barnhouse pointed out that love is central to all the fruits of the Spirit.
He said: “Love is the key—Joy is love singing—Peace is love resting—Long-suffering is love enduring—Kindness is love’s touch—Goodness is love’s character—Faithfulness is love’s habit—Gentleness is love’s self-forgetfulness—Self-control is love holding the reins.”
In other words, there can be no Fruit of the Spirit and thus no evidence of the presence of the Lord apart from love.