Bhagavad Gita 2.41
व्यवसायात्मिका बुद्धिरेकेह कुरुनन्दन। बहुशाखा ह्यनन्ताश्च बुद्धयोऽव्यवसायिनाम्॥
Easy meaning
A decided mind moves in one clear direction. An undecided mind splits into endless branches — and energy leaks everywhere.
When to use
Before study or deep work: choose one task, close the rest.