Charles Spurgeon Commentary 1 John 3:15

"Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him." — 1 John 3:15 (ASV)

And you know that no murderer has eternal life abiding in him.

His action is Cain-like; he is not of the chosen seed; he has not the life of God abiding in him.

Whosoever hates his brother is a murderer:

He would get rid of that brother if he could, and he is therefore a murderer in spirit, for the essence of murder is not the dagger or the poison, but the desire to put out of existence or to do the utmost harm to the one who is hated. The essential element of murder lurks within the heart of all hatred.