Bhagwad Gita
Chapter 13, Verse 5
ऋषिभिर्बहुधा गीतं छन्दोभिर्विविधैः पृथक्।ब्रह्मसूत्रपदैश्चैव हेतुमद्भिर्विनिश्िचतैः।।13.5।।
That knowledge of the field of activities and of the knower of activities is described by various sages in various Vedic writings-especially in the Vedanta-sutra-and is presented with all reasoning as to cause and effect.