"Traditionally, prayer flags are used to promote peace, compassion, strength, and wisdom. The flags do not carry prayers to gods, which is a common misconception; rather, the Tibetans believe the prayers and mantras will be blown by the wind to spread the good will and compassion into all pervading space. Therefore, prayer flags are thought to bring benefit to all.
By hanging flags in high places the Lung ta will carry the blessings depicted on the flags to all beings. As wind passes over the surface of the flags, which are sensitive to the slightest movement of the wind, the air is purified and sanctified by the mantras."
Larkya La Pass (5120m), Manaslu Region, Nepal