Nahj al-Balāgha
Hadith 1305صَلِّ الصَّلاَةَ لِوَقْتِهَا الْمُوَقَّتِ لَهَا، وَلَا تُعَجِّلْ وَقْتَهَا لِفَرَاغٍ، وَلَا تُؤْخِّرْهَا عَنْ وَقْتِهَا لِاشْتِغَالٍ، وَاعْلَمْ أَنَّ كُلَّ شَيْءٍ مِنْ عَمَلِكَ تَبَعٌ لِصَلاَتِكَ.
Say prayers at the appointed time. Do not say it earlier for the sake of (available) leisure nor delay it on account of pre-occupation. Remember that every act of yours is dependent on your prayer.