'One' in the Bible

And now I beseech thee, lady, not as though I wrote a new commandment unto thee, but that which we had from the beginning, that we love one another.

because many leading astray did enter into the world, who are not confessing Jesus Christ coming in flesh; this one is he who is leading astray, and the antichrist.

Anyone who does not remain in Christ’s teaching but goes beyond it, does not have God. The one who remains in that teaching, this one has both the Father and the Son.

if any one doth come unto you, and this teaching doth not bear, receive him not into the house, and say not to him, 'Hail!'

for the one who says, “Welcome,” to him shares in his evil works.