'In Christ' in the Bible
Yet I am writing you a new commandment, which is true (is realized) in Him and in you, because the darkness ( moral blindness) is clearing away and the true Light ( the revelation of God in Christ) is already shining.
But he who hates (detests, despises) his brother [ in Christ] is in darkness and walking (living) in the dark; he is straying and does not perceive or know where he is going, because the darkness has blinded his eyes.
By this it is made clear who take their nature from God and are His children and who take their nature from the devil and are his children: no one who does not practice righteousness [who does not conform to God's will in purpose, thought, and action] is of God; neither is anyone who does not love his brother (his fellow believer in Christ).
Anyone who hates (abominates, detests) his brother [in Christ] is [at heart] a murderer, and you know that no murderer has eternal life abiding ( persevering) within him.
If anyone says, I love God, and hates (detests, abominates) his brother [ in Christ], he is a liar; for he who does not love his brother, whom he has seen, cannot love God, Whom he has not seen.