Two things that are clear distinctions
1 John 3:10 In this the children of God and the children of the devil are manifest: Whoever does not practice righteousness is not of God, nor is he who does not love his brother.
I get it, two things exhibit being a child of God, everytime. 1st. Practicing righteousness, not perfection, but actually walking and doing what you Gods word says and 2nd. love. To love the LORD and each other. To love the unlovable in our eyes because Jesus also died and rose again to save them.