Ibn Kathir reported: Umar ibn Abdul Aziz, may Allah have mercy on him, said, “Speaking in remembrance of Allah Almighty is good, and thinking about the blessings of Allah is the best act of worship.”
Source: Tafsīr Ibn Kathīr 3:190
عن ابن كثير قَالَ عُمَرُ بْنُ عَبْدِ الْعَزِيزِ رحمه الله الْكَلَامُ بِذِكْرِ اللَّهِ عَزَّ وَجَلَّ حَسَنٌ وَالْفِكْرَةُ فِي نِعَمِ اللَّهِ أَفْضَلُ الْعِبَادَةِ
3:190 تفسير القرآن العظيم