After Guru Gobind Singh created the Khalsa in 1699, people across all sections of society began joining it in large numbers. However, both the state rulers and the pre-existing religious elites viewed this development as a threat to their own power. Mughal state administrators felt the democratic potential of the Khalsa, led by the people themselves, was incompatible with their imperial rule. Similarly, the Hindu priestly caste, the Brahmins, feared their followers would begin converting to the new faith, undermining the privileged and wealthy positions in society the Brahmins had so far been enjoying. Thus, Sikhism, a religion which sought to establish the common brotherhood of humankind regardless of religious or political affiliation, became a target for annihilation. All the forces opposed to Sikhism united in order to destroy the future of the new faith once and for all. They hoped that by murdering Guru Gobind Singh, they could throw the Khalsa into disarray and ultimately eliminate the movement.

In 1704, Guru Gobind Singh was completely surrounded at Anandpur Sahib by the joint armies of the emperor of Delhi, the Hindu hill rajas, and the governors of Lahore and Sirhind. Even this massive war machine could not defeat the Guru. The siege continued for many months, but to no avail. The Sikhs conducted a tenacious and successful defense. The financial burden of maintaining the soldiers laying siege to Anandpur Sahib put great strain on the attacking generals. To save face, they requested Guru Gobind Singh to voluntarily leave Anandpur Sahib and go elsewhere. By doing so, the Guru would not be harmed and the attackers could claim victory for having Anandpur Sahib vacated by the Guru. The Mughal generals swore on the Quran (Koran), and the Hindu generals swore on the cow, which they considered a holy animal, that the Sikhs would not be harmed if they voluntarily left Anandpur Sahib.

Because Guru Gobind Singh always wished to give peaceful means a chance whenever possible, he agreed to the offer. But as soon as the Sikhs left their fortifications, they were attacked by the joint militaries arrayed against them. Caught by surprise in the open, the Sikh force became scattered into small groups. Guru Gobind Singh himself had only forty men with him when he reached the village of Chamkaur. He and his men occupied a small mud building while thousands of opposing troops once again completely surrounded him.

The mud building was immediately attacked, but the Sikhs were determined to defend the Guru at all costs, and the attack was repulsed. One of the attacking generals was killed by an arrow shot by Guru Gobind Singh himself. The first unsuccessful assault was followed up by several more attacks that lasted the entire day. The eldest two of Guru Gobind Singh's four sons, Ajit Singh and Jujhar Singh, happened to be among the 40 men with the Guru. They sought no special status in relation to the other fighters, and both of them were killed defending the Guru.

By the time night fell, the army was encamped for miles in every direction around the building but had still been unable to crush the Sikh defense. The military forces were astounded that a handful of men could hold off thousands of elite troops for so long. Fear began to creep into their ranks. Meanwhile, the Guru decided to take tactical advantage of the night in order to break out of the mud building. The darkness would help even the odds if fighting started again. Guru Gobind Singh announced his departure with loud blasts on a horn. Most of the attacking forces, which had suffered heavy casualties during the day, were completely terrified of facing the Sikhs at night. They did not want to be the ones to die in order to murder the Guru for the rulers. Therefore, the Guru was able to pierce through miles of enemy encampments and escape with only limited resistance. As can be imagined, this result was a devastating blow to the prestige of the imperial Mughal forces and the hill rajas.

While the Guru's group was engaged in fending off the opposing army as described above, the Guru's mother and the two youngest of the Guru's four sons, Zorawar Singh and Fateh Singh, had been scattered into a different group when the Sikhs had been attacked by surprise at Anandpur Sahib. They were captured and brought to the ruler of Sirhind. Zorawar Singh was just nine years old, while Fateh Singh was seven. The Guru's mother, Mata Gujri, was elderly. The ruler did his best to convert the two children to Islam through bribes, threats, and torture. Despite their young age, he failed. Enraged by this, the Muslim administrator ordered that they be suffocated to death by being bricked alive inside a wall. The two children were made to stand while the wall was built up, brick by brick, around them. During the construction they were repeatedly given the offer to convert in exchange for their lives. They refused, and were eventually killed along with their grandmother.

When Guru Gobind Singh learned that all four of his children as well as his mother had been murdered, rather than despairing, he wrote the Zafarnama, or Letter of Victory, to Emperor Aurangzeb. He informed the Emperor:

You have harassed and killed many innocent people. Whereas you have engaged in plunder and deceit, breaking your sacred oath at Anandpur Sahib, I am on the path of truth and justice. By stamping out a few sparks (the Guru's family members), you have instead stoked the fire of the Khalsa. The Khalsa is alive and will remain so forever. The Khalsa will end your repression very soon.

In this section of Sikhism.com, we examine the Khalsa in which Guru Gobind Singh had such confidence.