אורח חיים תפ״הOrach Chayim 485

Se’if 1א׳

אָמַר: שְׁבוּעָה שֶׁלֹּא אֹכַל מַצָּה, סְתָם, אָסוּר לֶאֱכֹל מַצָּה בְּלֵיל פֶּסַח. אָמַר: שְׁבוּעָה שֶׁלֹּא אֹכַל מַצָּה בְּלֵיל פֶּסַח, לוֹקֶה וְאוֹכֵל מַצָּה בְּלֵיל פֶּסַח.

The Law Regarding One Who Swore Not to Eat Matzah (One Section): If a person swore generally, saying, "I swear not to eat matzah," he is forbidden to eat matzah on the night of Passover. However, if he specifically swore, "I swear not to eat matzah on the night of Passover," he receives lashes for taking an invalid oath and is still obligated to eat matzah on the night of Passover.