Sahih al-Bukhari 7464
Narrated Anas:
Allah's Messenger (ﷺ) said, "Whenever anyone of you invoke Allah for something, he should be firm in his 
asking, and he should not say: 'If You wish, give me...' for none can compel Allah to do something 
against His Will."
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ عَبْدِ الْعَزِيزِ، عَنْ أَنَسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ إِذَا دَعَوْتُمُ اللَّهَ فَاعْزِمُوا فِي الدُّعَاءِ، وَلاَ يَقُولَنَّ أَحَدُكُمْ إِنْ شِئْتَ فَأَعْطِنِي، فَإِنَّ اللَّهَ لاَ مُسْتَكْرِهَ لَهُ ‏"‏‏.‏