Simile of the Tortoise
SN 35.240 Kummopama Sutta: The Simile of the Tortoise
A tortoise sees a jackal and draws in its limbs and head to wait it out. The ‘jackal’ is Mara trying to get access through the senses, the ’limbs’. Guard the senses and don’t grasp at the ‘signs and features’ of anything.