Sri Guru Gobins Singh Ji had four sons; all four sons became Shaheed due to standing up for Sikh Principles. The elder two Baba Ajit Singh Ji and Baba Jujhar Singh Ji were killed in the battle of Chamkaur Sahib. The younger two were beheaded by the government because they refused to accept Islam. One day Mata Sahib Kaur Ji asked Sri Guru Gobind Singh Ji, whether he missed his sons?
Guru Ji Replied: You are wrong if you think I had only four sons, I have thousands of sons and daughters and in them I see the four I sacrificed. Those four sons were four virtues from Waheguru Ji, their body pots were to be smashed so that those virtues could be poured into the Khalsa.
Ajit means unconquerable, my Khalsa would rather die fighting than run like a coward.
Jujhar means warrior, my Khalsa is powerful and strong.
Zorawar means Power, as long as my Khalsa is distinct I will give them all of my power.
Fateh is victory, my Khalsa will fight for Waheguru's victory.
O Mata Jee, when I see one Khalsa with these 4 qualities I see all four sons.