Yoga Sutras of Patanjali · 1.43

स्मृतिपरिशुद्धौ स्वरूपशून्येवार्थमात्रनिर्भासा निर्वितर्का ॥४३॥

smṛtipariśuddhau svarūpaśūnyevārthamātranirbhāsā nirvitarkā

When memory is purified and the mind, as if empty of its own form, shines with the object alone, that is samadhi without reasoning.

— Yoga Sutras of Patanjali 1.43

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).