There is a very crucial point in spiritual practice – sentient beings and I are one. Do not differentiate between “you” and “me”. This is a key teaching. Therefore, we should visualize all sentient beings practicing together with us during a sadhana (prayer session), doing prostrations together and chanting the mantra together. The blessing power will purify your body. However, if you have not purified the rest of the sentient beings, you have in fact, not purified yourselves. Such visualization is very crucial. You should do as advised. This is a very superior method of practice of the Vajrayana.
If you fail to visualize that way during your sadhana, you are not a true Vajrayanist. This is a crucial point. When you do your prostrations, you are not just doing it alone and ignoring the rest of the sentient beings. On the contrary, you should visualize clearly, starting with one sentient being, gradually increasing the size to a row, and finally ending with the whole universe being filled with numerous sentient beings, who are doing prostrations together with you. Do every single step of the sadhana with the numerous sentient beings together is a key practice.
If you simply do your prostrations without doing such visualization, you are not a true Vajrayanist. You should practise with all sentient beings in mind, as one, receiving the blessing of the enlightened ones together, prostrating together, repenting together etc. The sentient beings have not broken free from the cyclic existence of birth and death, and therefore they are still ordinary beings. Whatever you do is a mere reflection of what they are. So, we, the Vajrayanists, should not gossip about others, as they are a mere reflection of what you are. We should not gossip about others but should be mindful about our own behavior instead. This is a key teaching that I hope you will bear in mind.