תּוֹרָה מג

When a person falls from faith — G-d forbid — the counsel for this is to speak faith with one's mouth — to say with a full mouth that one believes etc. For this itself — that one speaks words of faith with one's mouth — is the aspect of faith. Also through this one merits to come to complete faith. For faith depends on the mouth of the person — one must speak faith with the mouth as above — as it is stated: ""I will proclaim Your faithfulness with my mouth."" And likewise in the opposite direction — one must guard oneself greatly from bringing forth from one's mouth any word of heresy and atheism — G-d forbid — even in the manner of jest. That is — in one's heart one believes — but one says this word of heresy under another name and mocks it. Even this is a great prohibition — for it harms faith. For regarding Hashem Yisborach — it is forbidden to say words of jest — even in the manner of play. And one must guard oneself greatly — not to look at all at books that speak of inquiry. For they greatly harm and blemish the holy faith. And this warning has already been explained. But one must repeat it many times — lest one lose one's world in an instant — G-d forbid. Also the wisdom that exists in the service of Hashem itself — must also be greatly distanced. Namely — one who thinks and deliberates excessively and inquires whether one is fulfilling one's obligations in what one does. And searches after excessive stringencies. These wisdoms greatly bring a person down from the service of Hashem. And all these are confusions and imaginings from the accuser — to nullify one from one's service. And the Holy One, blessed be He, does not come with tyranny etc. And about these people it is stated: ""He shall live by them"" — and not that he shall die through them — for they have no vitality at all from the service and commandments they perform — because of their stringencies and their melancholy. And the greatest wisdom of all wisdoms — is to not be wise at all — only to serve Him, may He be blessed, in simplicity and wholeness. And the essence of the matter: for the Merciful One desires the heart.