Bhai dooj ancient story
The name of the wife of Lord Surya Narayan was Chhaya. Yamraj and Yamuna were born from his womb. Yamuna used to love Yamraj very much. She would request him to come to his house and have food with his favorite friends. Yamraj, who was busy with his work, kept postponing the matter. The day of Kartik Shukla has come. Yamuna again invited Yamraj for food that day, and promised him to come to her home.Yamraj thought that I am going to lose my life. Nobody wants to invite me to their home. It is my duty to follow the goodwill with which my sister is calling me. While coming to his sister's house, Yamraj freed the living beings who lived in hell. Yamuna's happiness knew no bounds when she saw Yamraj coming to her home. He took a bath after worshiping and served food to him. Yamraj, pleased with the hospitality extended by Yamuna, ordered the sister to ask for a boon.
Yamuna said that Bhadra! You come to my house on this day every year. Like me, the sister who treats her brother with respect on this day should not be afraid of you. Yamraj gave the invaluable garments to Yamuna by saying 'Tatastu' and made the way to Yamlok. From this day the tradition of the festival was formed. It is believed that those who accept hospitality do not fear Yama. That is why Yamraj and Yamuna are worshiped on Bhaiya Dooj.