How sound is the supplication: "Allah suffices us; Allah will give us of His bounty; indeed, we are desirous toward Allah," and is it a supplication, and is it permissible to say it?

The phrase mentioned is part of a verse in Surah At-Tawbah, and including it in supplication (Du'a) or supplicating with it is permissible. Some supplications take the form of praise or narration, such as the saying of Musa (Moses), peace be upon him: "My Lord, indeed I am, for whatever good You would send down to me, in need."