Bhagavad Gita Verse 2.68

इसलिये हे महाबाहो ! जिस पुरुषकी इन्द्रियाँ इन्द्रियोंके विषयोंसे सब प्रकार निग्रह की हुई हैं, उसीकी बुद्धि स्थिर है|

O ARJUNA, therefore with senses under control, protected from sensual objects, not only does one have the ability to reason things out properly, but also gains peace of mind leading to eternal bliss and happiness.