Sri Guru Nanak Dev Ji, the first Guru of the Sikhs, was born with the spiritual wisdom. This sword was used to destroy false rituals and beliefs which would never lead to union with waheguru. With this sword he denounced religious thugs and condemned ruthless kings and ministers as they were never condemned before.
You hold in your hands the sword of the Guru's spiritual wisdom; with this destroyer of death, kill the Messenger of Death. Ang 235 Sri Guru Granth Sahib Ji
Guru Angad Dev Ji, the second Guru of the Sikhs was given the sword of Spritaul wisdom, just like a candle lights another candle.
Nanak placed the umbrella of sovereignty on the head of Angad. He also graced the heart of Angad with the Mighty sword (Khaddag) of divine wisdom. Ang 966 Sri Guru Granth Sahib Ji
Guru Arjan Dev Ji, the fifth Guru of the Sikhs used martial metaphors in his shabads, he used these to arm his disciples with the sword of spirit. Without which no battle can be fought.
In His Mercy, God has blessed me with the sword of spiritual wisdom; I have attacked and killed the demons (Dark energies within us). Ang 1072 Sri Guru Granth Sahib Ji
Guru Hargobind Sahib Ji the 6th Guru , at the age of 11 put on two swords. One representing spiritual sovereignty (piri) and the other representing political sovereignty (miri). He showed the Sikhs to fight for both religious and political freedoms, religion without political freedom and dignity was abject slavery, and politics without religion was organised barbarism. Guru Gobind Singh Ji, the 10th Guru, stated that the sword was the symbol of Wahegurus power, Justice and saving grace through which he protects the virtuous and punished the wicked.
Sword that smiteth in a flash
That scatters the armies of the wicked
In the great battlefield
Thou are the symbol of the brave
Thine arm is irresistible thy brightness shine forth
The blaze of thou splendour dazzling like the sun
Sword, thou are the protector of the saints
Thou are the scourge of the wicked
Scatterer of the sinners, I take refuge in thee.
Victory to thee, sword: the savoir and sustainer
Victory to thee, Sword, supreme sword.
Bachitter Natak, Dasam Granth.