Significance of Shravan Purnima

That is the significance – purity in body, mind and speech.  In ancient days, women also had to wear this thread. It was not limited to only one caste. Everybody used to have to wear this whether they were Brahmins, Vaishya, Kshatriya, Shudra; but later on it got confined to a few. And on Rak sha Bandhan you tie the rakhi . It is the bond of protection where the sister protects her brother. And it does not have to be only their biological brother, in fact they even tie to whoever they consider a brother. Mind is so much connected with the moon, that is why whether it is a new moon or a full moon our mind meanders accordingly. Mind and the moon are very connected that is why in the vedas it is said, Chandrama Manaso Jata (Mind is not born from the moon, the moon is born from the mind). 

That is why these occasions are very important. It is said that for one to act; whether spiritual actions or worldly actions, one requires skill and ability. And to achieve this skill and ability we need to be responsible. Only a responsible person can carry out his duties. And the sacred thread ceremony signifies how to take responsibility.