Yōga Sūtra 2.45

समाधिसिद्धिरीश्वरप्रणिधानात्।

samādhisiddhirīśvarapraṇidhānāt।

[समाधि सिद्धिः इश्वर प्रणिधानात्।
samādhi = equllibrium state of chitta; siddhiḥ = mastery; iśvara = Īshwara, the Lord; praṇidhānāt = surrender to;]

Surrender to Īshwara, the Lord, gives mastery of samādhi.