The most beloved speech to Allah is ...

قَالَ عَبْدُاللهِ : إِنَّ مِنْ أَحَبِّ الْكَلَامِ إِلَى اللهِ أَنْ يَقُولَ الْعَبْدِ : اللَّهُمَّ أَعْتَرِفُ بِالذَّنْبِ وَأَبُوءُ بِالنِّعْمَةِ فَاغْفِرْلِي إِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ

‘Abdullah ibn Mas’ud رضي الله تعالى عنه said:

The most beloved speech to Allah is for the servant to say:

‘O Allah! I confess my sin and acknowledge Your blessing, so forgive me for none forgives (and none is able to forgive) sin except You.’