Bhagavad Gita · Chapter 2: The Path of Understanding
Bhagavad Gita 2.41
व्यवसायात्मिका बुद्धिरेकेह कुरुनन्दन ।
बहुशाखा ह्यनन्ताश्च बुद्धयोऽव्यवसायिनाम् ॥
vyavasāyātmikā buddhirekeha kurunandana | bahuśākhā hyanantāśca buddhayo'vyavasāyinām ||
On this path, Arjuna, the resolute understanding is single. The thoughts of the irresolute branch out in many directions and have no end.
Modern context
A settled mind has one aim; an unsettled mind has countless aims branching in every direction. This reads like a description of modern attention, split between tasks, tabs and ambitions. Krishna's point is that a clear single purpose is what gathers a person's energy; without it, effort leaks away in a hundred directions.