עֶרְיָ֤ה תֵעוֹר֙ קַשְׁתֶּ֔ךָ שְׁבֻע֥וֹת מַטּ֖וֹת אֹ֣מֶר סֶ֑לָה נְהָר֖וֹת תְּבַקַּע־אָֽרֶץ׃
주께서 활을 꺼내시고 살을 바로 발하셨나이다 (셀라) 주께서 하수들로 땅을 쪼개셨나이다
Rashi
perpetual statement A statement that is to last forever. אֹמֶר is vowelized with a “pattah,” [meaning a “seggol”] and the accent is on the first syllable, making it a noun.