Alternatively, the Tzemach Dovid explains the pasuk to mean that Moshe davened that Pharaoh should say shira instead of the frogs, as this would be an even bigger Kiddush Hashem. Therefore, the pasuk says that he davened — ‘that the matter of the frogs should be placed on Pharaoh.’
The Tefillah Must be Explained:
The concept of tefillah is mentioned several times in the story of the exodus from Egypt in regards to the prayers of Moshe Rabenu and Klal Yisroel during the bondage, and for the redemption. Furthermore, we can learn an important lesson in regards to tefillah from these stories. The Ohr Hachaim Hakadosh states that we learn from the frogs that one must say his tefillos out loud, in a clear way, with his requests fully explained.