وَأَسْبَابُهَا أَوْقَاتُهَا، وَتَجِبُ بِأَوَّلِ الْوَقْتِ وُجُوبًا مُوَسَّعًا
The prayer time is the apparent legal cause bringing the prayer obligation into effect. At the beginning of the time the obligation is normally spacious: the prayer may be performed within the valid window, although deliberate delay into a prohibited or dangerously narrow period can be sinful.