2,637. Retracting Mentally Only

Hilchos Shevuos 2:18

Similar to the case in the previous halacha, let’s say that others tell the one who took an oath to retract, or that the thing he prohibited upon himself is permitted to him, or similar such things. If he accepts their statement within the time that it takes to speak by saying “Yes” or “I retract,” then he is permitted. After the time it takes to speak has passed, he can no longer retract.

Hilchos Shevuos 2:19

If someone took an oath and he retracted in his heart within the time that it takes to speak, it has no effect. Similarly, let’s say that others tell him to retract, or that the prohibited thing is permitted to him, or that his oath is absolved. If he accepts their words in his heart within the time that it takes to speak, it makes no difference. One must verbalize his retraction the same way he did his oath.