Their core teaching is that the majority of people only have one hope - a fleshly hope. They teach that the majority of humans cannot enter enter the Kingdom of the Heavens.
A scripture they use all the time is 1 Corinthians 15:33. But they never quote anything else from that chapter. If they just kept read from that verse to the end of the chapter, they would stop talking about "what sort of body" the dead are raised up in, and stop saying that when Jesus said that in the resurrection, people will be like the angels and neither marry nor be given in marriage means that you will no longer have genitals but will still have a fleshly body.
" 35 Nevertheless, someone will say: “How are the dead to be raised up? Yes, with what sort of body are they coming?” 36 You unreasonable person! What you sow is not made alive unless first it dies; 37 and as for what you sow, you sow, not the body that will develop, but a bare grain, it may be, of wheat or any one of the rest; 38 but God gives it a body just as it has pleased him, and to each of the seeds its own body. 39 Not all flesh is the same flesh, but there is one of mankind, and there is another flesh of cattle, and another flesh of birds, and another of fish. 40 And there are heavenly bodies, and earthly bodies; but the glory of the heavenly bodies is one sort, and that of the earthly bodies is a different sort. 41 The glory of the sun is one sort, and the glory of the moon is another, and the glory of the stars is another; in fact, star differs from star in glory.
42 So also is the resurrection of the dead. It is sown in corruption, it is raised up in incorruption. 43 It is sown in dishonor, it is raised up in glory. It is sown in weakness, it is raised up in power. 44 It is sown a physical body, it is raised up a spiritual body. If there is a physical body, there is also a spiritual one. 45 It is even so written: “The first man Adam became a living soul.” The last Adam became a life-giving spirit. 46 Nevertheless, the first is, not that which is spiritual, but that which is physical, afterward that which is spiritual. 47 The first man is out of the earth and made of dust; the second man is out of heaven. 48 As the one made of dust [is], so those made of dust [are] also; and as the heavenly one [is], so those who are heavenly [are] also. 49 And just as we have borne the image of the one made of dust, we shall bear also the image of the heavenly one.
50 However, this I say, brothers, that flesh and blood cannot inherit God’s kingdom, neither does corruption inherit incorruption. 51 Look! I tell YOU a sacred secret: We shall not all fall asleep [in death], but we shall all be changed, 52 in a moment, in the twinkling of an eye, during the last trumpet. For the trumpet will sound, and the dead will be raised up incorruptible, and we shall be changed. 53 For this which is corruptible must put on incorruption, and this which is mortal must put on immortality. 54 But when [this which is corruptible puts on incorruption and] this which is mortal puts on immortality, then the saying will take place that is written: “Death is swallowed up forever.” 55 “Death, where is your victory? Death, where is your sting?” 56 The sting producing death is sin, but the power for sin is the Law. 57 But thanks to God, for he gives us the victory through our Lord Jesus Christ!"
(1 Corinthians 15:34-57)