What is the ruling on saying, "And the last of our دعاء is praise be to Allah," before the taslim in prayer?

There is no harm in concluding a supplication with the words: "And the last of their call will be: 'Praise be to Allah, Lord of the worlds'" or "Praise be to Allah, Lord of the worlds" in prostration (sujud), or during qunut, or before the salutation (taslim), or outside of prayer. This is in emulation of the people of Paradise, who conclude their supplications with these words, as stated in His Almighty's saying: ﴿Their call therein will be, "Glory be to You, O Allah!" and their greeting therein will be, "Peace!" And the last of their call will be, "Praise be to Allah, Lord of the worlds."﴾