The Prophet ﷺ said: If anyone sits in his place of prayer when he finishes the dawn prayer till he prays the two rak'ahs of the forenoon, saying nothing but what is good, his sins will be forgiven even if they are more than the foam of the sea. (Using translation from Abū Dāʾūd 1287)   

أَنَّ رَسُولَ اللهِ ﷺ قَالَ مَنْ قَعَدَ فِي مُصَلَّاهُ حِينَ يَنْصَرِفُ مِنْ صَلَاةِ الصُّبْحِ حَتَّى يُسَبِّحَ رَكْعَتَيِ الضُّحَى لَا يَقُولُ إِلَّا خَيْرًا غُفِرَ لَهُ خَطَايَاهُ وَإِنْ كَانَتْ أَكْثَرَ مِنْ زَبَدِ الْبَحْرِ