"Indeed the supplication stops between the heavens and the earth. Nothing of it is raised up until you send Salat upon your Prophet."

إِنَّ الدُّعَاءَ مَوْقُوفٌ بَيْنَ السَّمَاءِ وَالأَرْضِ لاَ يَصْعَدُ مِنْهُ شَيْءٌ حَتَّى تُصَلِّيَ عَلَى نَبِيِّكَ ﷺ