We were in the company of Messenger of Allah ﷺ (during Hajj). Whenever we went up a high place we used to say: "None has the right to be worshipped but Allah, and Allah is Greater," and our voices used to rise, so the Prophet ﷺ said, "O people! Be merciful to yourselves (i.e. don't raise your voice), for you are not calling a deaf or an absent one, but One Who is with you, no doubt He is All-Hearer, ever Near (to all things).  

عَنْ أَبِي مُوسَى الأَشْعَرِيِّ ؓ قَالَ كُنَّا مَعَ رَسُولِ اللَّهِ ﷺ فَكُنَّا إِذَا أَشْرَفْنَا عَلَى وَادٍ هَلَّلْنَا وَكَبَّرْنَا ارْتَفَعَتْ أَصْوَاتُنَا فَقَالَ النَّبِيُّ ﷺ يَا أَيُّهَا النَّاسُ ارْبَعُوا عَلَى أَنْفُسِكُمْ فَإِنَّكُمْ لاَ تَدْعُونَ أَصَمَّ وَلاَ غَائِبًا إِنَّهُ مَعَكُمْ إِنَّهُ سَمِيعٌ قَرِيبٌ تَبَارَكَ اسْمُهُ وَتَعَالَى جَدُّهُ