Raksha bahandan, also known as Rakhi Pournima, is a very auspicious and divine day in Sanatana dharma (Hindu Tradition) and celebrated on is celebrated on sravan masam pournima day every year. This is a very special festival revealing the strong bonding prevailing between brothers and sisters, and also projects the greatness of stringent Indian family system. Usually sisters tie raksha (rakhi) to their brothers. This festival portrays the great significance in Hindu mythology. The main theme of this festival is to assure women protection and security in the society.
Women is given superior position in the Hindu mythology, where it is stated that all the thrimurthies (brahma, Vishnu and maheswara) got their powers from Adi Parashakthi. Almost all beautiful things in this nature are compared and signified with female gender only, such is the importance given to the women. Even nature is termed with female gender, as ‘Goddesses Prakrti! That is the greatness a woman possess. In simple words women can be revered with the statement : यत्र नार्यस्तु पूज्यन्ते रमन्ते तत्र देवता: | Meaning that wherever women is worshiped there dwells all the gods. This raksha bhandan festival authenticates this fact once again. That is beauty of this festival.

Reasons behind this festival celebration:
For the first time goddess Parvathi (also known as Adi Para Shakthi) tied raksha to her brother Lord Maha Vishnu. The underlying fact is that, she offered her divine powers through raksha (rakshi).This brings out the underlying fact that every women in this creation is an incarnation of Adi para shakthi and when women offers pooja to the rakhi wishing all good for her brother, then all the divine powers of Goddesses of Parvathi will be embedded in the rakhi. Before tying rakhi, women treating her brother as lord Vishnu puts thialk on brother’s forehead exactly at Ajneya chakra, gives harathi (like offered to god) and takes blessings. The beauty of this raksha bhandan is that brother and sister find the god inside each other to that they offer pranams for the wellbeing of each other. Accepting raksha bhandan is promising in the name of gods that we protect our sister whatsoever situation she might be in. This raksha bhandan protects a brother in all his bad times, makes him to travel in a righteous path and achieve all the success.

It is advisable to chant the following mantra while doing raksha dharana to your brother:

                                                                                                  येन बद्धो वली राजा दानवेन्द्रो महाबलः ।
                                                                                                  तेन त्वा प्रतिबध्नामि रक्षे माचल माचल ॥

Another auspicious thing is, this is also called as Yajnopaveeth festival. Meaning that all bramhins change their yajnopaveeth on this day and perform sacred japas and prayers with a lot of divinity. This marks the starting day of vedic education in the gurukulas. Many of bramhin sect are to perform homas and yajnas today with full of divine heart for the wellbeing of the society. In past it is believed that Draupadi devi tied raksha bhandan to Lord Shri Krishna, which is why lord Krishna always protected Draupadi in all her difficult times.