Wikipedia
Sugrivajne ( Sugriva pledge) ( kannada:ಸುಗ್ರೀವಾಜ್ಞೆ) is a popular pledge that appeared in the Ramayana & Mahabharata. Since then, the word "Sugrivajne" has often been used in Indian politics denoting a Bill or Act that must be passed or obeyed in a timely fashion.
In the Ramayana, '''Sugrivajne '''is found within the Yuddha Kāṇḍa. In this book, Hanuman (the popular monkey god) introduces Lord Rama to his exiled King Sugriva, at Mount Rishyamukah. This exile has been brought about from a supposed betrayal by Sugriva against his elder brother Vali the king of Kishkindha, who now also holds his wife.
Lord Rama is at this time on a quest to rescue his wife Sita from the demon Ravana, king of the Rakshasas. Sugriva shows Rama the items that Sita had dropped whilst she traveled overhead in the clutches of Ravana. Rama makes a suggestion to kill Vali and reinstate Sugriva as King if Sugriva, in turn, pledges to help Rama with his quest. Sugriva accepts & goes to challenge Vali. An evenly matched combat ensues between the brothers, and after some time Hanuman helps Rama kill Vali.
Sugriva claims the kingdom, takes back his wife Rumā, and Vali's widow Tara is made Empress. Sugriva dismisses his earlier promise to help Rama and is threatened with death but Hanuman and Tara persuade him otherwise and so Sugriva takes his army south to free Sita from Ravana.
In the battle Sugriva challenges and fights with the Rakshasa Kumbhakarna, a brother of Ravana, and no doubt would have killed Surgriva but for the timely intervention of Rama's brother Lakshmana.
Thus Sugriva fulfills his pledge.