First Timothy 1:19-20 says, "Holding faith and a good conscience; which some having put away, concerning the faith have made shipwreck: of whom is Hymeneus and Alexander; whom I have delivered unto Satan, that they may learn not to blaspheme." Do you think that Alexander and Hymeneus were real Christians? Even the Bible indicates that they were evil ones. No doubt they were terrible tares.
Second Timothy 4:14-15 mentions Alexander the coppersmith again: "Alexander the coppersmith did me much evil: the Lord reward him according to his works: of whom be thou ware also; for he hath greatly withstood our words." Evil here means damage—Alexander did Paul much damage.
Now let us read Hebrews 12:15: "Looking carefully lest any one be falling away from the grace of God, lest any root of bitterness springing up trouble you, and through this many be defiled." The root of bitterness here indicates some persons who may spring up to trouble and defile you. They will become persons of bitterness. No doubt these are the false ones.
"But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction. And many shall follow their pernicious ways; by reason of whom the way of truth shall be evil spoken of. And through covetousness shall they with feigned words make merchandise of you: whose judgment now of a long time lingereth not, and their damnation slumbereth not" (2 Pet. 2:1-3). This is really terrible! Surely these were the false Christians, the tares.
From the same chapter we read verse 15: "Which have forsaken the right way, and are gone astray, following the way of Balaam the son of Beor, who loved the wages of unrighteousness." Then verses 17-22: "These are wells without water, clouds that are carried with a tempest; to whom the mist of darkness is reserved forever. For when they speak great swelling words of vanity, they allure through the lusts of the flesh, through much wantonness, those that were clean escaped from them who live in error. While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage. For if after they have escaped the pollutions of the world through the knowledge of the Lord and Savior Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them. But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire." Here are unclean and dirty things: dogs and swine. What awful, terrible, and ugly terms are used to describe these kinds of false Christians: the wolves, the dogs, and the swine. These three awful things are tares among the Christians. The wolf is so damaging, and the dogs and swine are so dirty.