In plain words
The bad in one enters the good in another. The good in one enters the bad in another. So at the time of dhyāna there must be no contact between one body and another. I do not mean meditation alone. In any circumstances at all, when someone mixes with others with the feeling of the body, the bad feelings in them enter this one like a current. So, as far as possible, it is very good to stay apart. It was with that intention that all the ṛṣis went to the forest. When we have contact with evil feelings, those very evil feelings come into us. It is very necessary, as far as possible, to live alone to some extent, with no contact between one and another. This is the secret of the Divine.