This practice requires the student to have permission/empowerment received from a qualified master in order to engage in the self-generation of the deity. However, it is permitted to do this practice without such an empowerment as long as you do not generate yourself as the deity. Instead, you should generate the deity at the crown of your head or in front of you instead of self-generation.
The practice of Vajra Armor is especially powerful to cure diseases such as cancer and to remove spirit harm and other hindrances. If one practices it every day and uses the mantra to bless water, the water can be taken by oneself and also given to others to heal them. Short practice translated by Lama Zopa Rinpoche and Thubten Pemba.
3 Pages. 2011 Edition.