وَلَا يُقَلِّبُ الْحَصَى إِلَّا أَنْ لَا يُمْكِنَهُ السُّجُودُ عَلَيْهِ، فَيُسَوِّيهِ مَرَّةً وَاحِدَةً.
Meaning: Do not turn over pebbles unless proper prostration is impossible; then level them once.
One necessary adjustment differs from repeatedly touching the ground without need.