KATHMANDU: President Bidya Devi Bhandari has offered best wishes to all followers of Sikhism at home and abroad on the occasion of the 550th birth anniversary of Guru Nanak Dev, the first Sikh Guru and founder of Sikh faith. In a message, the president expressed hope that national unity would be strengthened through tolerance and goodwill among religious, social and cultural groups by following the guidelines given by Guru Nanak that seeks to maintain harmony among all religions for peace, and protection and for the welfare of humans. May this occasion help all make their contributions to society by following the message of Guru Nanak, she said in the message.