Verse
यतो यतो निश्चरति मनश्चंचलमस्थिरम् ।ततस्ततो नियम्यैतद् आत्मन्येव वशं नयेत् ॥
yato yato niścarati manaścaṃcalamasthiramtatastato niyamyaitad ātmanyeva vaśaṃ nayet
Whenever the restless and unquiet mind goes forth, it should be controlled and brought into subjection in the Self.
Gītā 6·26