Devotional service in Krsna consciousness cannot be performed blindly due to material emotion or mental concoction. It is specifically mentioned here that one has to perform devotional service in full knowledge by visualizing the Absolute Truth. We can understand about the Absolute Truth by evolving transcendental knowledge, and the result of such transcendental knowledge will be manifested by renunciation. That renunciation is not temporary or artificial, but is very strong. It is said that development of Krsna consciousness is exhibited by proportionate material detachment, or vairagya. If one does not separate himself from material enjoyment, it is to be understood that he is not advancing in Krsna consciousness. Renunciation in Krsna consciousness is so strong that it cannot be deviated by any attractive illusion. One has to perform devotional service in full tapasya, austerity. One should fast on the two Ekadasi days, which fall on the eleventh day of the waxing and waning moon, and on the birthdays of Lord Krsna, Lord Rama and Caitanya Mahaprabhu. There are many such fasting days. Yogena means by controlling the senses and mind. Yoga indriya-samyamah. Yogena implies that one is seriously absorbed in the self and is able, by development of knowledge, to understand his constitutional position in relationship with the Superself. In this way one becomes fixed in devotional service, and his faith cannot be shaken by any material allurement.