व्यवसायात्मिका बुद्धिरेकेह कुरुनन्दन। बहुशाखा ह्यनन्ताश्च बुद्धयोऽव्यवसायिनाम् ॥

vyavasāyātmikā buddhir ekeha kuru-nandana bahu-śhākhā hyanantāśh cha buddhayo ’vyavasāyinām

The determinate Reason is but one-pointed, O joy of the Kurus; many-branched and endless are the thoughts of the irresolute.

In plain words: Krishna, calling Arjuna joy of the Kurus (his family line), says a firm mind is focused on one goal. A person who can't decide has endless scattered thoughts going in every direction.