The following excerpt adapted from Living Reality by Bhai Sahiba Dr. Bibiji Inderjit Kaur Khalsa, Page 74-75.
Guru Gobind Singh gave the kara, a steel bangle that women wear on their left wrist, and men wear on their right wrist. The kara is a sign of slavery and freedom. Guru Gobind Singh made us a slave to God so that we can be free of everything. The kara is a sign that we bow only to God and serve only the Infinity; that we are never a slave to any man. He made it of steel to remind us that our steel will be tested, and our commitment shall never falter. He made it round to symbolize our oneness with the Infinite – the Akal Purkh – the boundless, undying, Almighty God.