"And those who are regarding their prayers" [meaning: the five prayers] "guard them" by maintaining their ablution, their prescribed times, their bowing, and their prostrating.
﴿وَالَّذين هم على صلواتهم﴾ [يَعْنِي: الصَّلَوَاتِ الْخَمْسَ] ﴿يُحَافِظُونَ﴾ عَلَى وضوئها ومواقيتها وركوعها وسجودها