Chapter 2, Verse 58
yadā saṁharate cāyaṁ
kūrmo’ṅgānīva sarvaśaḥ
indriyāṇīndriyārthebhyas
tasya prajñā pratiṣṭhitā
He who withdraws his senses from the objects of sense, as the tortoise withdraws his limbs into his shell, his intelligence sits firmly founded in wisdom.
This verse speaks of withdrawing the senses from all objects of self-enjoyment at the time of meditation, thus depriving them of their power to distract the mind and the intellect. Like a tortoise pulls all his limbs inside, leaving only the shell outside, like that, one has to dive within oneself. You can’t pull your hands inside you, but by entering into the cave of the heart, being aware, and sitting in deep, full concentration within oneself, this is true wisdom. But if one is sitting in meditation, yet one is not there, one is somewhere else, that is not true meditation. How many people sit to meditate, but the moment they close their eyes, they ask themselves, “Where am I? I don’t even know where I am!” They are somewhere else.
Once there was a yogi who invited all his students to sit for meditation. As they were all sitting, he told them, “Okay, now go into the Self.” Everybody closed their eyes, started breathing and went within. When the meditation was over, the yogi asked, “Who was really here during this meditation?” Everybody was thinking, “Oh, I was in America”; “Ah, my parents!” “I was here,” and “I was there.” They were not fully focused. They were all over the place. Even here, how many of you are really listening to me? If I scream, of course, this will bring you back here. But some of you are elsewhere, even though you appear to be listening and watching. You are watching, but you are not seeing anything, because your mind is somewhere else. When the mind is focused in the Self, that is true wisdom. Then it can’t be elsewhere. Nothing can distract it; nothing can move it.
Bhagavad Gita