Immediately after salam of the witr prayer

Subḥāna ‘l-Maliki ‘l-Quddūs. [Recite three times, and raise and extend the voice on the third time and say...] Rabbi ‘l-Malā'ikati war-rūh.

Glory is to the King, the Holy. [Recite three times in Arabic, and raise and extend the voice on the third time and say...] Lord of the angels and the Spirit.

[ An-Nasa'i 3/244, Ad-Daraqutni and others. The final addition is from Ad-Daraqutni's version 2/ 31 and its chain of narration is authentic. See the checking of Zadul-Ma'ad by Shu'aib Al-Arna'ut and 'Abdul-Qadir Al-Arna'ut 1/337. Hisn al-Muslim 119 ]