"There are no days greater and more beloved to Allah than these ten days, so increase in them the tahlīl (saying, 'lā ilāha illā allāh'), the takbīr (saying, 'allāhu akbar'), and taḥmīd (saying, 'al-ḥamdu lillāh') (Using translation from Aḥmad 5446)
عَنِ النَّبِيِّ ﷺ قَالَ مَا مِنْ أَيَّامٍ أَعْظَمُ عِنْدَ اللهِ وَلَا أَحَبُّ إِلَيْهِ الْعَمَلُ فِيهِنَّ مِنْ هَذِهِ الْأَيَّامِ الْعَشْرِ فَأَكْثِرُوا فِيهِنَّ مِنَ التَّهْلِيلِ وَالتَّكْبِيرِ وَالتَّحْمِيدِ