Bhai Mati Das and Bhai Sati Das, both brothers, were sons of Bhai Hira Nand. Their ancestor, Gautam Das, was a resident of village Kariala in Jehlum district. He was initiated into Sikh faith by Guru Arjan.

Their grandfather, Bhai Praga, had been given command of a 'Jatha' (unit) by Guru Hargobind in the first battle with the Mughals in 1628 CE. He died of deep wounds sustained in that battle. After that, Bhai Hira Nand presented himself in the service of Guru Har Rai. Before his death in 1657 CE, he left Bhai Mati Das and Bhai Sati Das, elder of his four sons, in the service of Guru-ghar. In accordance with the command of their father, they started serving the Guru with heart and soul.

Bhai Mati Das and Bhai Sati Das accompanied Guru Harkrishan when he went to Delhi on invitation of a vassal king of Aurangzeb. After the merger of the Guru into the Supreme Being on the 30th March, 1664 CE, both the brothers went to village Bakala. On the manifestation of Guru Tegh Bahadur, both the brothers presented themselves in his service. When Dhir Mall could not become the Guru, he made a fruitless attempt to shoot the Guru in collaboration with Shihan Masand and his gang. After that he had taken away valuable items from the Guru's institution to his camp. At that time both the brothers gave all the help to Makhan Shah to present Dhir Mall and Shihan Masand in bondage before the Guru.

One day, Durgah Mall, the Diwan (chief minister) of Guru-ghar requested the Guru, "O True Emperor ! My body, soul and worldly wealth are all at your service but it is becoming difficult for me to carry out the duty of Diwan due to old age. These two nephews are in your service who are trustworthy and faithful sons. If you deem fit bestow my duties on them." Accepting the request of Diwan Durgah Mall, the Guru entrusted the duties of Diwan to Bhai Mati Dass and Wazir to Bhai Sati Dass.

In order to bring the whole of the Indian subcontinent under one faith, Aurangzeb ordered in 1674 CE, to convert Hindus to Islam by force. The governor of Kashmir started implementing the order in right earnest. Before bowing their heads before the sword of Sher Afghan Khan, the Governor of Kashmir, the prominent Brahmins of Kashmir led by Pandit Kirpa Ram appeared before the Guru at Anandpur on the 25th May, 1675 CE, and explained about their helplessness. The Guru knew that weak and terrified people do not become brave by listening to episodes of bravery. Fearless and great leadership is needed to make them fearless. So the Guru said to them, "Go and tell the governor and the emperor that if you convert Guru Tegh Bahadur to Islam, we shall become Muslims of our own accord." On getting this message, Aurangzeb ordered the arrest of the Guru. For courting arrest, the Guru started towards Agra from Anandpur on the 11th July, 1675 CE. At Agra, when the soldiers came to arrest the Guru, both the brothers were also arrested.

On receipt of the second order from Aurangzeb, the Guru was asked to embrace Islam. The Guru refused. In order to intimidate the Guru, the qazis (Islamic theologians adjudicating in accordance with teachings of Islam) made a plan to torture to death the Sikhs arrested with the Guru before his eyes. They thought that the Guru would embrace Islam out of fear on seeing the horrendous death of his Sikhs. The qazis decreed to cut Bhai Mati Das with a saw first of all.

Hearing the order of the qazis, Bhai Mati Das bowed to the Guru, "O True King ! bless me so that I may do my duty by sacrificing myself for the glory of the faith." After the Guru had blessed him, the qazis again exhorted Bhai Mati Das to embrace Islam, "Brother, embrace Islam and enjoy the pleasures provided by the government. Moreover when you die as a Muslim, you will go to heaven where there will be streams of milk, many kinds of wine to drink and beautiful women to enjoy. If you do not embrace Islam, your body will be sawn into two." Bhai Mati Dass replied, "I can sacrifice hundreds of such heavens for my faith. I don't need women nor wine. I see all the happiness in the path of my faith." After his refusal, the qazis asked him his last wish, to which he replied, 'When I am being cut with the saw, let my face be towards my Guru so that I may behold him till my last breath and he may see how happily I reach my last destination." By the order of the qazis, the executioners sawed Bhai Mati Dass in two on the 8th November, 1675 CE, at Chandani Chowk, Delhi.On the 9th of November, Bhai Dayal Das boiled alive. For detail see the section on Bhai Dayal Das.

On the 10th November, 1675 CE, the qazis ordered Bhai Sati Dass to be wrapped in cotton wool and burnt alive. Before being wrapped in cotton, the qazis asked Bhai Sati Das, "Save your life by embracing Islam and live in pleasure." Bhai Sati Das replied, 'You cannot understand that my pleasure and happiness lie only in obeying the command of my Guru. It does not lie in saving this life which must end one day." At this reply, the executioners wrapped Bhai Sati Das in cotton, poured oil over it and set fire to it. Bhai Sati Das remained calm while burning till his last breath and remained true to his resolve.