اَللَّهُمَّ رَبَّنَا لَكَ الْحَمْدُ مِلْءَ السَّمَوَاتِ وَمِلْءَ الْأَرْضِ وَمِلْءَ مَا بَيْنَهُمَا وَمِلْءَ مَا شِئْتَ مِنْ شَيْءٍ بَعْدُ

Alla-humma Rabbanaa lakal ‘hamdu mil-as samawaati wa mil-al ardi wa mil-aa maa baina humaa, wa mil-aa maa shi’ta min shayin ba’du

Praise be to You, O Allah, our Lord! Praise be to You, it fills the heavens, fills the earth, completes all that is in between them, and then it completes whatever You will. Ibn Abi Aufa (R), Ibn Abbas (RA), Ali (RA) and other Companions said that the Prophet (ﷺ) used to say these words when he stand up from rukoo'.

Reference: Muslim: 476