Rashi on Exodus 9:3/רש"י על שמות ט׳:ג׳

1‎הנה יד ה׳ הוֹיָה BEHOLD THE HAND OF THE LORD IS — The verb הויה is in the present tense, for so one says in the feminine gender of the past היתה, “she was”, of the future, תהיה, “she will be” and of the present, הוֹיָה, the latter form being similar to עוֹשָׂה and רוֹצָה and רוֹעָה (Fem. part. sing. Kal of ל"ה verbs).