Abuse leads to sinful conduct. (SSS Vol.17, p. 20)

Do not slander or abuse others or your own selves, as weak, sinful wicked or low; when you do so, you are slandering or abusing Me, who resides in them and you. All are of the Divine Nature of the Atma; all are pure and holy. Some might have erred in using the intelligence and discrimination which the Lord has given and so might have been guilty of ‘mistakes’; they are not therefore, ‘sinful.’ To condemn oneself as ‘Paapoham paapasambhavah,’ (I am a sinner born of sin) is’ itself the direst Papa (sin)! Use your intelligence and march on, putting one milestone after another behind you!

As a matter of fact, do not cast a bad word on man or beast; for He is in all Beings and your harsh abuse strikes the Dweller within. (SSS Vol.2, p. 2/103)

Indulging in abuse of others or inflicting pain on them is not a sign of human nature. (SSS Vol.17, p. 28)

Just as your own voice is reflected back by the echo, your actions return to you as reactions. Hence, you should learn not to abuse anyone or harm anyone. Good and bad are nothing but reflections of your own inner being. It is on the basis of this truth that I advise, people to be good, see good and do good as the way to God. (SSS Vol.22, p. 77)