Bhagwad Gita
Chapter 2, Verse 62
ध्यायतो विषयान्पुंसः सङ्गस्तेषूपजायते।
सङ्गात् संजायते कामः कामात्क्रोधोऽभिजायते।।2.62।।
While thinking about the things that please our senses, a person can start to feel strongly attached to them. This attachment then leads to desire, and from that desire, anger can emerge.