Śaṅkaraon Brahma Sūtra 4.1.9
Advaita Vedānta
Sūtra
अचलत्वं चापेक्ष्य
acalatvaṃ cāpekṣya
Sūtra translation
And with reference to immobility (scripture ascribes thought to the earth, &c.).
Moreover, in the passage ‘ The earth thinks as it * were scripture ascribes thought to the earth, with regard to its immobility. This also helps us to infer that meditation is the occupation of one who is sitting.