SB 11.18.13
istva yathopadesam mam
dattva sarva-svam rtvije
agnin sva-prana avesya
nirapeksah parivrajet
Translation:
Having worshiped Me according to scriptural injunctions and having given all one’s property to the sacrificial priest, one should place the fire sacrifice within oneself. Thus, with the mind completely detached, one should enter the sannyasa order of life.
Purport:
One cannot maintain the sannyasa order of life unless one gives up all materialistic association and engages exclusively in devotional service to the Supreme Lord. Any material desire will gradually prove to be a stumbling block in the prosecution of renounced life. Therefore, a liberated sannyasi must vigilantly keep himself free from the weeds of material desires, which surface principally in the form of attachment to women, money and reputation. One may possess a beautiful garden filled with fruits and flowers, but without vigilant maintenance the garden will be overrun by weeds. Similarly, one who achieves a beautiful state of Krsna consciousness takes the sannyasa order of life, but if he does not vigilantly and painstakingly keep his heart clean, there is always the danger of a relapse into illusion.