The Greek word apoplanao is only found twice in the New Testament. The first use is in Mark 13:22, where it is rendered as seduce. The second is in 1 Tim. 6:10, where it is translated as err.

In Mark, the atttempted seduction is offered by means of signs and wonders. “For false Christs and false prophets shall rise, and shall shew signs and wonders to seduce, if it were possible, even the elect” (Mark 13:22). What men find compelling is often the result of what they want to find compelling, and this means that if a man cannot read his own heart, then he will not be able to read a miracle in the sky, even if the miracle is fifty yards across and bright red. The antithesis governs epistemology.

In 1 Timothy, the problem is caused by the love of money. “For the love of money is the root of all evil: which while some coveted after, they have erred from the faith, and pierced themselves through with many sorrows” (1 Tim. 6:10). Wandering off from the faith was caused by the love of money, a sin which many do not notice — since it is quite a respectable sin.

The word apistos is rendered in a number of different ways, but all of them relate to the sin of unbelief.

Paul refers to those “that believe not” in the context of marriage. A Christian spouse is not bound if he or she has a husband or wife who doesn’t believe, and who does not want to remain married (1 Cor. 7:12,13). The same word is rendered as unbelieving three times in the next two verses (1 Cor. 7:14-15), still referring to the non-Christian spouse.

If someone who “believes not” invites a Christian to a feast, he should certainly feel free to go (1 Cor. 10:27).

The gift of tongues was given for those who “believe not” (1 Cor. 14:22, 24), while prophesy is for believers. We can see the impact of a right use of these gifts if an unbeliever comes into the service (1 Cor. 14:23).

The word is translated as unbelieving in two places. Nothing is pure for the defiled and unbelieving (Tit. 1:15). The lake of fire is reserved for, among others, the unbelieving (Rev. 21:8).

Another rendition is faithless, and we have one example of this from each gospel. When His disciples could not heal a demon-possessed boy, Jesus lamented His perverse and faithless generation (Matt. 17:17; Mk. 9:19; Luke 9:41). In the gospel of John, Jesus told Thomas not to be faithless, but rather to believe (John 20:27).

The word can also mean unbeliever. The servant who abuses the others will be assigned a portion with the unbelievers (Luke 12:46). The apostle was appalled that the Corinthian Christians were willing to go to law against each other before unbelievers (1 Cor. 6:6). We are not to be yoked together with unbelievers (2 Cor. 6:14). The same word is rendered as infidel in the next verse (2 Cor. 6:15). And a man who does not care for his own family is worse than an infidel (1 Tim. 5:8).

The god of that age had blinded the minds of those who had not believed (2 Cor. 4:4).

And in one place Paul uses the word to refer to a “thing incredible” (Acts 26:8), referring to unbelief in the resurrection.

We have already considered the verb that expressed unbelief (apisteo), and the noun apistia is obviously related

Jesus did not do many miracles in His hometown because of their unbelief (Matt. 13:58; Mk. 6:6). The disciples were unable to cast out a particularly stubborn demon because of their unbelief (Matt. 17:20). It is striking that in Mark’s account of that same incident the father of the demon-possessed boy cried out for Jesus to save him from his own unbelief (Mk. 9:24) Jesus rebuked His disciples after the resurrection for their reluctance to believe those who had reported Him risen (Mark 16:14).

Paul exults in the fact that the unbelief of man is incapable of thwarting the faith of God (Rom. 3:3). When Abraham was promised a son in his old age, he did not stagger in unbelief (Rom. 4:20). The unbelieving Jews were broken off the olive tree of the true Israel because of unbelief (Rom. 11:20), and if they give up that unbelief, they will be grafted back in again (Rom. 11:23). Before Paul was converted, he was an evil man, and like his countrymen was caught in the web of unbelief (1 Tim. 1:13).

Christians are told to guard against the sin of unbelief (Heb. 3:12), a sin that results in departing from the living God. The Jews in the wilderness could not enter into God’s rest because of unbelief (Heb. 3:19). In the same way today, Christians are to resist unbelief, a sin that remains a sin even if we give it a fancy theological name.

Influenced by certain Enlightenment assumptions, we like to believe that we all may reserve the right to not believe certain things. But in Scripture to “believe not” is described as a sin. The verb used to describe this unbelief in Scripture is apisteo.

The male disciples had been told by Jesus that He was going to come back from the dead, and then when He did, and the women testified that they had seen Him, refused to believe anyway. “And they, when they had heard that he was alive, and had been seen of her, believed not”(Mk 16:11). “And their words seemed to them as idle tales, and they believed them not”(Lk 24:11). Of course they were eventually persuaded, and their shock at that time is described in a figure of speech that was not sinful. They believed not “for joy” (Luke 24:41)

Jesus tells His disciples that the message they were to preach to the nations was a winnowing message. “He that believeth and is baptized shall be saved; but he that believeth not shall be damned”(Mk 16:16). And this is how the message has worked from the first century until now. Some who hear believe, and others do not. “And some believed the things which were spoken, and some believed not” (Ac 28:24).

God is not thrown down from His throne by unbelief. How could that be? “For what if some did not believe? shall their unbelief make the faith of God without effect?”(Ro 3:3). God will work out His good purposes regardless of the unbelief shown by the ultimate rebels, and He will work over, around, through, and into the temporary unbelief of His weak children. “If we believe not, yet he abideth faithful: he cannot deny himself”(2 Ti 2:13).

We have already consider one word for threatening (apeileo), and we now come to another closely related one (apeile). As before, threatening is something the ungodly do.

In one place, the two words are used together, for straitly and for threatening. “But that it spread no further among the people, let us straitly threaten them, that they speak henceforth to no man in this name”(Acts 4:17). And when they had done so, the disciples spoke of it just a few verses later. “For of a truth against thy holy child Jesus, whom thou hast anointed, both Herod, and Pontius Pilate, with the Gentiles, and the people of Israel, were gathered together, For to do whatsoever thy hand and thy counsel determined before to be done. And now, Lord, behold their threatenings: and grant unto thy servants, that with all boldness they may speak thy word”(Ac 4:28-29).

We can see the sinful frame of mind that Saul of Tarsus was in as he engaged in his attack on the fledgling Christian church. “And Saul, yet breathing out threatenings and slaughter against the disciples of the Lord, went unto the high priest, And desired of him letters to Damascus to the synagogues, that if he found any of this way, whether they were men or women, he might bring them bound unto Jerusalem”(Ac 9:1-2). And of course later, this same man (now transformed) instructed Christians who were masters of slaves to make sure they did not attempt to govern them in this sinful way. “And, ye masters, do the same things unto them, forbearing threatening: knowing that your Master also is in heaven; neither is there respect of persons with him.(Eph 6:9). God’s people ought not to function with threats really at all.

The word apeileo means to threaten, and is used twice in the New Testament. In both instances it is cited as a sinful kind of behavior. When the Jewish leaders were trying to shut down the apostles early in the book of Acts, one of the means they tried was that of threats. “But that it spread no further among the people, let us straitly threaten them, that they speak henceforth to no man in this name” (Acts 4:17). And Jesus, when He was being abused by the religious authorities, refused to respond to them in kind. “For even hereunto were ye called: because Christ also suffered for us, leaving us an example, that ye should follow his steps: Who did no sin, neither was guile found in his mouth: Who, when he was reviled, reviled not again; when he suffered, he threatened not; but committed himself to him that judgeth righteously” (1 Pet. 2:21-23).