Mohammed IS mentioned in the Bible, but not by name.
“Then if anyone says to you, ‘Look, here is the Christ!’ or, ‘There!’ do not believe it. For false Christs and false prophets will rise and show great signs and wonders to deceive, if possible, even the elect. See, I have told you beforehand. Therefore if they say to you, ‘Look, He is in the desert!’ do not go out; or ‘Look, He is in the inner rooms!’ do not believe it’ ” (Matthew 24:23-26, NKJV).
“I am afraid that just as Eve was deceived by the serpent’s cunning, your minds may somehow be led astray from your sincere and pure devotion to Christ. For if someone comes to you and preaches a Jesus other than the Jesus we preached, or if you receive a different spirit from the one you received, or a different gospel from the one you accepted, you put up with it easily enough” (2 Corinthians 11:3, 4, NIV).
“For such men are false apostles, deceitful workmen, masquerading as apostles of Christ. And no wonder, for Satan himself masquerades as an angel of light. Is it not surprising, then, if his servants masquerade as servants of righteousness. Their end will be what their actions deserve” (2 Corinthians 11:13-15, NIV).
Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world. By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God, and every spirit that does not confess Jesus is not from God. This is the spirit of the antichrist, which you heard was coming and now is in the world already. Little children, you are from God and have overcome them, for he who is in you is greater than he who is in the world. They are from the world; therefore they speak from the world, and the world listens to them. (1 John 4: 1-6)
Jesus said to him, “I am the way, and the truth, and the life. No one comes to the Father except through me. (John 14:6)