They asked the Baal Shem Tov, “The Talmud tells us that for everything G‑d forbade, He provided us something permissible of the same sort. If so, what did He permit that corresponds to the sin of heresy?”
The Baal Shem Tov replied, “Acts of kindness.”
Because when you see a person suffering, you don’t say, “G‑d runs the universe. G‑d will take care. G‑d knows what is best.” You do everything in your power to relieve that suffering as though there is no G‑d. You become a heretic in G‑d’s name.