Khalid al-'Absi said, "A son of mine died and I felt intense grief over his loss. I said, 'Abu Hurayra, have you heard anything from the Prophet, may Allah bless him and grant him peace, to cheer us regarding our dead?' He replied, 'I heard the Prophet, may Allah bless him and grant him peace, say, "Your children are roaming freely in the Garden."'"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَيَّاشٌ، قَالَ: حَدَّثَنَا عَبْدُ الأَعْلَى، قَالَ: حَدَّثَنَا سَعِيدٌ الْجُرَيْرِيُّ، عَنْ خَالِدٍ الْعَبْسِيِّ قَالَ: مَاتَ ابْنٌ لِي، فَوَجَدْتُ عَلَيْهِ وَجَدَا شَدِيدًا، فَقُلْتُ: يَا أَبَا هُرَيْرَةَ، مَا سَمِعْتَ مِنَ النَّبِيِّ صلى الله عليه وسلم شَيْئًا تُسَخِّي بِهِ أَنْفُسَنَا عَنْ مَوْتَانَا؟ قَالَ: سَمِعْتُ مِنَ النَّبِيِّ صلى الله عليه وسلم يَقُولُ: صِغَارُكُمْ دَعَامِيصُ الْجَنَّةِ.
sunnah.com