Bhai Subeg Singh was a resident of village Jumber in district Lahore. He was a scholar of Persian. He was working as a government contractor at Lahore. He mediated between the government and the Sikhs in 1733 CE, when the Dal Khalsa was given an estate.

After the death of Zakria Khan on the 1st July, 1745 CE, his son, Yahiya Khan became the Governor of Lahore. To avenge the death of his brother Jaspat Rai, who had died in an encounter with the Singhs near Eminabad in January, 1746 CE, Diwan Lakhpat Rai said to the new Governor, "Subeg Singh is in league with the Singhs. Your father had to hit himself on the head with a Singh's shoe at his bidding which caused his death. He should be punished for that crime."

The Governor ordered Bhai Subeg Singh to become a Muslim and spy on the Singhs. Bhai Subeg Singh refused point blank and was arrested. Eighteen year old son of Bhai Subeg Singh, Shahbaz Singh, studied Persian from a maulvi. When the maulvi came to know of the arrest of Bhai Subeg Singh, he asked Bhai Shahbaz Singh to embrace Islam so that he may marry his daughter to him as he was very handsome and a genius. Bhai Shahbaz Singh refused his offer. The maulvi asked the Governor and had him arrested also. The qazi said to them, "If both of you embrace Islam, you will be pardoned. " At their refusal both of them were mounted on death-wheels in sight of each other so that they might embrace Islam seeing each other suffering. But they did not forsake their faith although both became unconscious due to excessive loss of blood.

Next day, the qazi said to Bhai Shahbaz Singh, "Son ! your father has been executed. I can ward off your death if you become a Muslim even now." Bhai Shahbaz Singh replied, "Death cannot be put off. It must come one day." The qazi sent the son away, called for the father and said to him, 'Your son has agreed to embrace Islam and you should also consent to do so." Bhai Subeg Singh said, "I cannot give up my faith at any cost." The qazi again brought the father and son face to face. He again asked both of them to come to the fold of Islam. On their refusal, the qazi ordered both of them to be killed. On the 10th March, 1746 CE, the executioners beheaded both of them. It was on that day that Diwan Lakhpat Rai had got together the Sikhs of Lahore and handed them over to the scavengers of the city for slaughter in order to exterminate Sikhs. The prominent citizens of the city pleaded with the Diwan not to murder innocent Sikhs. He replied, "If God Himself comes and forbids me, I shall not stop."