“Many general-folk and ignorant people (who do not know the Religion as they ought to) believe it is allowed for them to delay their daytime prayers till the evening or night time due to the least of tasks that keep them busy. He thinks that praying in the evening (to make up what he missed in the day) is better than praying at the correct time in the day due to him being occupied with work. This thinking is false according to the consensus (ijmā’) of the Muslim scholars. Rather, it is unbelief (kufr). And many of them think that is not allowed to pray on time unless they can complete all of the actions of the prayer―and that if he was to delay the prayer until after its time so that he can fulfil completely all of its actions, then that is better than praying on time. This thinking is false and futile, rather it is kufr (unbelief).” (See Minhāj As-Sunnah, 5/230)
“Whoever says, ‘I will not pray the daytime prayer until the night-time’ is just like the one who says, ‘I will not fast the month of Ramadān until the month of Shawwāl.’ So the one who believes it is permitted for him to delay the pray like that, then he also believes it is allowed for him to delay the fast of Ramadān―and whoever believes in these two affairs is commanded to repent according to the consensus (ijmā’) of the scholars. If he repents and believes in praying on time and fasting on time, he is left alone, otherwise [if he persists], he is punished [by the courts] and executed.” (See Minhāj As-Sunnah, 5/230).
“Indeed delaying the prayer until after its time deliberately is not accepted [in Islam] from the one who does that. And the sin of not praying is not removed from him even if he makes qadā (makes up the prayer later) ―and this is agreed upon by the Muslim scholars.” (See Majmoo’ Al-Fatāwa of Shaikhul-Islām Ibn Taymiyyah, 21/456)
“And there is no differing among the Muslims scholars that if a traveller, who has no water with him, knows that he will find water after the prayer time is passed, then it is not allowed for him to delay the prayer so that he prays it after its time with wudū or ghusl (if he is in janābah)―rather it obligatory that he prays on time. Likewise, the one who is unable to make rukū’ or sujūd or is unable to recite ―if he believes that it is permissible* not to pray, then he is an unbeliever, without a doubt.” (See Majmoo’ Al-Fatāwa of Shaikhul-Islām Ibn Taymiyyah, 22/56)
* i.e. Makes it halāl for himself to delay (or avoid) the prayer.