The Bal Shem Tov once said:
The commandment that one must have the trait of Bitachon (absolute trust in G-d) is only on one’s self.
When some misfortune befalls man, he must, according to the Torah, do all that he can and the place his trust in G-d, that He will surely help and save him.
However, for an individual to use the trait of trust in G-d for their fellow is considered a sin.
Someone who sees his fellow’s misfortune and says “G-d will help him,” is a completely evil thing to say. One must exert themselves in prayer and begging for mercy for their fellow.
(Igros Kodesh, Previous Lubavitcher Rebbe, Vol. 3 Pg. 76)
