The Messenger of Allah (ﷺ) said: "Indeed the one who betrays will have a banner erected for him on the Day of Judgement."

There are narrations on this topic from 'Ali, 'Abdullah bin Mas'ud, Abu Sa'eed Al-Khudri, and Anas.

This Hadith is Hasan Sahih. I asked Muhammad about the Hadith of Suwaid, from Abu Ishaq, from 'Umarah bin 'Umair, from 'Ali, from the Prophet (ﷺ) who said: "For every person who betrays there will be banner." He said: "I do not know of this Hadith being Marfu'"
Jami` at-Tirmidhi Book 21, Hadith 43
← Previous Hadith "I heard Sulaim bin 'Amir saying: 'There was a treaty between Mu'awiyah and the people of Rome. He was making an expedition into their lands so that when the period of the treaty was expires he would attack them. So when a man upon an animal' - or - 'upon a horse said: "Allahu Akbar! Fulfillment not betrayal!" - and it turned out to be 'Amr bin 'Abasah - Mu'awiyah asked him about that. He said: "I heard the Messenger of Allah (ﷺ) said: 'Whoever has a treaty between himself and a people, then let him not violate the treaty nor try to change it until its time has passed, or , in retribution for a similar offense.'" He said: "So Mu'awiyah returned with the people."

This Hadith is Hasan Sahih.

Jami` at-Tirmidhi Book 21, Hadith 42 Next Hadith → "On the day of (the battle of) Al-Ahzab, Sa'd bin Mu'adh was struck by an arrow such that the upper vein or lower vein of his forearm was severed. So the Messenger of Allah (ﷺ) tried to stop it with fire, but it made his arm bleed profusely so he left it. Then he did it another time but it caused it to bleed profusely. Upon seeing that he said: 'O Allah! Do not allow my soul depart until my eyes are comforted by elimination of Banu Quraizah.' He pressed his vein closed and it did not bleed a drop before they surrendered to the arbitration of Sa'd bin Mu'adh. He (the Prophet (ﷺ)) sent to him (Sa'd) who judged that their men should be killed, their women should be spared, and that the Muslims may share them among themselves. With this, the Messenger of Allah (ﷺ) said: 'You have judged according to Allah's judgement for them.' And they were four hundred. Then when he finished killing them, his vein opened up and he died."

There are narrations on this topic from Abu Sa'eed and 'Atiyyah Al-Qurazi.

This Hadith is Hasan Sahih.

Jami` at-Tirmidhi Book 21, Hadith 44