The Prophet ﷺ said, "There is no Muslim who loses three children who have not yet reached the age of accountability except that Allah will admit him into Paradise through the abundance of His mercy toward them."
قال النبي ﷺ: ما من الناس من مسلم يتوفى له ثلاث لم يبلغوا الحنث إلا أدخله الله الجنة بفضل رحمته إياهم.
Bukhari (1248) narrated it from Abu Muamar, who said, Abdul-Warith narrated to us, who said, Abdul-Aziz narrated to us, from Anas, and he mentioned the like of it.His saying, "by the grace of His mercy upon them" means that mercy is greater for young children, since sin does not occur from them. Its meaning is that people enter Paradise by the grace of Allah's mercy for their children, if they seek reward and show patience. If parents enter Paradise by the grace of Allah's mercy for their children, this indicates that the children of Muslims are in Paradise. This is the position of the majority of Muslim scholars, except the Mujbirah, who say, "They are subject to Allah's will."