According to a legend, when Hanumanji was in Lanka and his tail was set on fire, Shani Dev was also present there and he was impressed by Hanumanji’s force and challenged him for war. In the war, Hanumanji defeated Shani Dev and suffered injuries on his body, causing him to peel. When Shani Dev apologized to Hanumanji, Hanumanji gave mustard oil to calm his body, which relieved Shani Dev from pain. After this incident, Shani Dev promised that the devotees who offer oil to him will be removed and their grace will remain.
