In the Testament of Reuben, who was the first son of Jacob/Israel, Reuben expounds in detail on the evils of fornication; which is fitting for a man who raped his father's concubine, Bilhah. The Apostle Paul would appreciate Reuben's anti-woman sentiment.
On his deathbed, and after some details to set the Testament in motion (1:1-5), Reuben explains how God punished him with a painful venereal disease for seven months for defiling his father's bed (1:6-8).
Reuben went into concerted repentance for seven years, during which time he learned of the seven (actually eight) spirits "against man" which are opposed to the seven (actually eight) spirits given to man to do his work. Spirits given to man are life, sight, hearing, smell, speech, taste, procreation/sexual intercourse, and sleep. The opposing spirits are fornication (in the senses), insatiability (in the belly), fighting (in the liver and gall), obsequiousness and chicanery, pride, lying, injustice, and wicked dreams while asleep. These spirits cause the downfall of young men (1:7-31).
Reuben advises to avoid women (1:32-34). Because he saw Bilhah bathing naked, he couldn't stop thinking about her. So when he saw her passed-out drunk and naked, he raped her without her knowing (1:35-40). God told Jacob/Israel about the rape, and so he never again had sex with Bilhah (1:41).
Reuben advises his sons not to even think about women until God gives them a wife, and in that way they can avoid the guilty shame which haunted him since the Bilhah affair (2:1-6). Fornication kills men before their time and couples them to Beliar (Belial) (2:7-8). It was because Joseph protected himself from Potiphar's wife that God protected and rewarded him (2:9-11). If you can overcome fornication you can overcome Beliar (2:12)
Women are evil because they use sexual attraction to gain power over men, or resort to other tricks if that doesn't work. Women are more prone to fornication than men. Command your wives and daughters to appear modest or even ugly, because women who fornicate are bound for eternal punishment (2:13-17).
It was the immodesty and deviant allure of women which caused the fall of the Watchers (fallen angels), who took the form of men to have sex with them (ref. Genesis 6:1-2). Their offspring were the pre-Flood giants (2:18-19, Nephilim, ref. Genesis 6:4).
So stay away from women, and women should stay away from men, to avoid the evils of fornication (2:20-23).
Reuben knows that his progeny will rebel against Levi's progeny. However, they should instead respect the Tribe of Levi, because they will have the Law of God, and will be appointed to provide judgements and offer sacrifices as High Priests until the "consummation of the times." They should deal truthfully with their neighbors and love their brothers. They should also bow to the Tribe of Judah, because God has made them king of the nation, and they fight visible and invisible wars, and they will "be among you an eternal king" (2:24-30).
Then Reuben died (2:31).
Reuben does not contain much that could be called specifically Christian prophesy, but that doesn't mean that it lacks an apparent relationship to the New Testament writings.
Reuben 1:16 says that the spirit spirit given to a man is "the sense of hearing, with which cometh teaching," which is possibly, although unlikely, related to the "faith comes from hearing" sentiment of Romans 10:17.
The general message throughout most of Reuben against fornication is included in the New Testament, such as 1 Corinthians 6:18, 2 Corinthians 12:21, Galatians 5:19, Ephesians 5:3, and Colossians 3:5.
Reuben 2:17 speaks against women adorning themselves for beauty in a fashion echoed in 1 Timothy 2:9-10 and 1 Peter 3:3-5. Also, while Reuben 2:20-23 does not recommend avoiding marriage completely, its sentiment of avoiding the opposite sex is somewhat similar in nature to the 1 Corinthians 7:25-40 speech regarding abstaining from marriage altogether if you can in order to have a pure and fully devoted life for God.
Along the lines of prophesy regarding Jesus, Reuben 2:24-30 is less obvious than many of the other Testaments. The tribe of Levi will supply the High Priests until the "consummation of the times" (Reuben 2:26), which could mean until Jesus comes, but is also similar to pre-Christian Jewish eschatology. Reuben 2:30 states that the Tribe of Judah would fight invisible wars, echoed in Ephesians 6:12. Reuben 2:30 also says that the Tribe of Judah would "be among you an eternal king," which could mean that it would supply Jesus' lineage, but could also mean that the tribe would simply provide an unbroken lineage of rulers.
We see in Reuben 2:17 the prescription of eternal punishment for fornicators, which is still a popular Christian doctrine, but is also a common theme pre-Christian Jewish eschatology of the 4BC-1BC time frame.
Finally, in Reuben 2:8 and Reuben 2:12 we see Beliar fighting against men in the same ways which Christianity claims Satan is fighting against them.
"And I tell you that [God] smote me with a sore plague in my loins for seven months; and had not my father Jamb prayed for me to the Lord, the Lord would have destroyed me." - Reuben 1:7
"The third, the spirit of fighting, in the liver and gall." - Reuben 1:26 (from back when they believed different organs controlled different emotions)
"And so perisheth every young man, darkening his mind from the truth, and not understanding the Law of God, nor obeying the admonitions of his fathers, as befell me also in my youth." - Reuben 1:32 (speaking about the Law of God centuries before it was given to Moses)
"Having therefore gone in and beheld [Bilhah's] nakedness, I wrought the impiety without her perceiving it, and leaving her sleeping departed." - Reuben 1:40 (regarding the rape of Bilhah)
"For until my father's death I had not boldness to look in his face, or to speak to any of my brethren, because of the reproach." - Reuben 2:2 (also regarding the rape of Bilhah)
"For many hath fornication destroyed; because, though a man be old or noble, or rich or poor, he bringeth reproach upon himself with the sons of men and derision with Beliar." - Reuben 2:8
"For evil are women, my children; and since they have no power or strength over man, they use wiles by outward attractions, that they may draw him to themselves." - Reuben 2:13
"For moreover, concerning them, the angel of the Lord told me, and taught me, that women are overcome by the spirit of fornication more than men, and in their heart they plot against men; and by means of their adornment they deceive first their minds, and by the glance of the eye instil the poison, and then through the accomplished act they take them captive." - Reuben 2:15
"For constant meetings, even though the ungodly deed be not wrought, are to [women] an irremediable disease, and to us a destruction of Beliar and an eternal reproach." - Reuben 2:22
"And bow down before [Judah's] seed, for on our behalf it will die in wars visible and invisible, and will be among you an eternal king." - Reuben 2:30