Is it permissible to say, "Under the wings of His Mercy"?

Mercy is an attribute firmly established for Allah the Almighty in the Qur’an and Sunnah, and "Ar-Rahman" (The Most Merciful) and "Ar-Rahim" (The Bestower of Mercy) are among His names. Mercy and blessing, when attributed to Allah, are of two types: the attribution of an effect to its doer (which is created mercy, like Paradise and rain), and the attribution of an attribute to the one described by it (which is the mercy that is an attribute of Allah). As for the phrase "under the wings of His mercy," if it refers to the attribute, then it is an error and impermissible, because the باب الصفات (chapter of attributes) is tawqifi (restricted to what is stated in revelation). However, if it refers to created mercy, there is no harm in it, but it is preferable to use beautiful and well-attested phrases found in the sacred texts.