In the Testament of Gad, who was the ninth son of Jacob/Israel, Gad expounds upon the evils of hatred, and commands his progeny to love one another.
At the age of one hundred and twenty five, Gad gathered together his sons to impart his life lessons (1:1).
Gad was a valiant and skilled shepherd, capable of killing any beast threatening the flocks (1:2-3).
Joseph had a misunderstanding and told Jacob/Israel that Gad and his other brothers had slayed the best of the flock for themselves. This incident, Jacob's/Israel's favoritism for Joseph, and Joseph's prophetic dreams drove Gad hate Joseph, even to the point of wanting to kill him, but God saved Joseph by having Judah sell him (1:4-14).
Gad advises his progeny to work righteousness and obey God's Law, and to avoid hatred. Hatred skews your perspective, blinds you to the truth, provokes envy, promotes evil-speaking, causes arrogance, leads you astray from God's Law, and makes you revel in the punishment and death of others (as opposed to love, which would be merciful) (1:15-23). Satan works with the spirit of hatred to cause death, but love works with God's Law for the Salvation of men. Hatred causes many kinds of evil (1:24-25).
Gad implores his progeny to learn from his experience, and to drive out hatred and instead seek righteousness. A righteous man will not wrong anyone else, even in his thoughts, for fear of God (1:26-30).
Gad learned these things when he repented regarding Joseph, because that repentance brought him knowledge and Salvation. God had punished Gad with a disease of the liver (the organ which drives wrath, ref. Naphtali 1:20) for eleven months because of his anger for Joseph (1:31-36).
Gad advises his progeny to love one another, put aside hatred, speak peaceably and do not rebuke those who sin against you, keep secrets which may provoke others to anger, let God take care of vengeance, do not envy or be jealous but rather pray for the prosperity of others, remember that all flesh will die, praise God, seek God's judgement, let God handle those who become rich through evil means, and remember that God loves a poor man who is without envy (2:1-16).
Gad reminds his progeny to honor Levi and Judah, because God's Salvation will come from them. However, Gad knows that his progeny will depart from God in the last days (2:17-18).
Then Gad died (2:19-21).
Gad has little in terms of Christian prophesy, but a great deal in terms of Christ-like living.
Gad's general message against hatred is found in the New Testament in Galatians 5:20, Titus 3:3, 1 John 2:9-11, 1 John 3:15, and 1 John 4:20.
In Gad 1:11, Gad 1:23, Gad 2:2 equate hate with a desire to murder, similar to Jesus' message in Matthew 5:21-22.
Gad 1:19, Gad 2:1, Gad 2:3, Gad 2:16 all harp on loving your neighbor, which is common to Matthew 22:37-39, Mark 12:29-31, Mark 12:33, Luke 10:27, Romans 13:8-10, Galatians 5:14, and James 2:8.
Gad 1:24 speaks of how love works with God's Law to bring Salvation, which is almost like Romans 13:8-10.
Gad 1:28 explains how people are reproved by their own hearts, just like in Romans 2:15.
Gad 1:30 states that a righteous man will avoid sinning even in thought, promoting the idea that thoughts can be sinful and evil, like we find in Matthew 9:4, Matthew 15:19, Mark 7:21, Acts 8:22, Ephesians 2:3, and James 2:4.
Gad 1:32 speaks of how repentance brings Salvation, similar to 2 Corinthians 7:10.
Gad 2:3 is close to an enactment of Luke 17:3-4 as far as the treatment of someone who sins against you.
In Gad 2:8 we find that if someone persists in wronging you, you are to just (implicitly) let him (like Matthew 5:38-41), forgive him (like Matthew 6:14-15), and let God handle the vengeance (like Romans 12:19).
In Gad 2:14 unrepentant people are destined for eternal punishment.
Gad 2:15 claims that poor men are loved and blessed by God, as we could gather from Matthew 5:3 and Luke 6:20.
Gad 2:17 places Israel's Salvation coming from the Tribes of Levi and Judah. Consider that Matthew 1:1-17 has Jesus' lineage of Joseph traced through the tribe of Judah, and many Biblical scholars suggest that Luke 3:23-38 has Jesus' lineage traced through Mary, and hold that Mary had bloodline ties to Levi (although they are under some dispute where exactly the Levitical bloodline enters).
Finally, regarding Beliar (Belial), he gets no mention in this Testament; a status which Gad holds in common only with Zebulun. However, Gad 1:24 states that Satan uses hatred and Gad 1:26 claims that hatred is of the devil, which are sentiments quite at home with Christianity doctrine.
"Accordingly I guarded at night the flock; and whenever the lion came, or the wolf, or any wild beast against the fold, I pursued it, and overtaking it I seized its foot with my hand and hurled it about a stone's throw, and so killed it." - Gad 1:3
"And the spirit of hatred was in me, and I wished not either to hear of Joseph with the ears, or see him with the eyes, because he rebuked us to our faces saying that we were eating of the flock without Judah." - Gad 1:9
"And now, my children, hearken to the words of truth to work righteousness, and all the law of the Most High, and go not astray through the spirit of hatred, for it is evil in all the doings of men." - Gad 1:15 (reference to God's Law hundreds of years before it would be Biblically given)
"For [hatred] will not hear the words of His commandments concerning the loving of one's--neighbour, and it sinneth against God." - Gad 1:19
"For the spirit of hatred worketh together with Satan, through hastiness of spirits, in all things to men's death; but the spirit of love worketh together with the law of God in long-suffering unto the salvation of men." - Gad 1:24 (yet God's Law commands for a lot of death)
"Hatred, therefore, is evil, for it constantly mateth with lying, speaking against the truth; and it maketh small things to be great, and causeth the light to be darkness, and calleth the sweet bitter, and teacheth slander, and kindleth wrath, and stirreth up war, and violence and all covetousness; it filleth the heart with evils and devilish poison." - Gad 1:25
"For he that is just and humble is ashamed to do what is unjust, being reproved not of another, but of his own heart, because the Lord looketh on his inclination." - Gad 1:28
"For fearing lest he should offend the Lord, he will not do wrong to any man, even in thought." - Gad 1:30
"For true repentance after a godly sort destroyeth ignorance, and driveth away the darkness, and enlighteneth the eyes, and giveth knowledge to the soul, and leadeth the mind to salvation." - Gad 1:32
"For God brought upon me a disease of the liver; and had not the prayers of Jacob my father succoured me, it had hardly failed but my spirit had departed. For by what things a man transgresseth by the same also is he punished. Since, therefore, my liver was set mercilessly against Joseph, in my liver too I suffered mercilessly, and was judged for eleven months, for so long a time as I had been angry against Joseph." - Gad 1:34-36 (Gad's liver caused his wrath, so God afflicted it!)
"And now, my children, I exhort you, love ye each one his brother, and put away hatred from your hearts, love one another in deed, and in word, and in the inclination of the soul." - Gad 2:1
"Love ye one another from the heart; and if a man sin against thee, speak peaceably to him, and in thy soul hold not guile; and if he repent and confess, forgive him." - Gad 2:3
"And if he be further exalted, be not envious of him, remembering that all flesh shall die; and offer praise to God, who giveth things good and profitable to all men." - Gad 2:11 ("Remember that all flesh shall die" is an odd phrase which would seem to be a reminder that this life is short, but the next would be eternal.)
"For if he taketh away from a man wealth gotten by evil means He forgiveth him if he repent, but the unrepentant is reserved for eternal punishment." - Gad 2:14 (eternal punishment...)
"For the poor man, if free from envy he pleaseth the Lord in all things, is blessed beyond all men, because he hath not the travail of vain men." - Gad 2:15 (blessed are the poor...)
"Do ye also therefore tell these things to your children, that they honour Judah and Levi, for from them shall the Lord raise up salvation to Israel."- Gad 2:17 (Consider that Matthew 1:1-17 has Jesus' lineage of Joseph traced through the tribe of Judah, and many Biblical scholars suggest that Luke 3:23-38 has Jesus' lineage traced through Mary, and hold that Mary had bloodline ties to Levi.)