'Whom' in the Bible

[I am writing about] what existed from the beginning, what we have heard, what we have seen with our eyes, what we have looked at and touched with our hands, concerning the Word of Life [the One who existed even before the beginning of the world, Christ]—

But whoever continually keeps his commandments is the kind of person in whom God's love has truly been perfected. This is how we can be sure that we are in union with God:

The one who keeps His commandments abides in Him, and He in him. We know by this that He abides in us, by the Spirit whom He has given us.

and every spirit who doesn't confess that Jesus Christ has come in the flesh is not of God, and this is the spirit of the Antichrist, of whom you have heard that it comes. Now it is in the world already.

If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen?