What he told Muadh to never stop saying
He held his hand first and told him he loved him.
رَبِّ أَعِنِّي عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ
Rabbi aʿinnī ʿalā dhikrika wa shukrika wa ḥusni ʿibādatik
“My Lord, help me to remember You, to thank You, and to worship You well.”
Say it after the tashahhud, before the salām.
Where this comes from
He took Muadh by the hand and said: I love you, Muadh. Muadh said: and I love you. Then came the gift. Never stop saying this after every prayer. Notice that even remembering Him is something you ask His help for.
The full narration
It was narrated that Mu'adhbin Jabal said:"The Messenger of Allah (ﷺ) took my hand and said: 'I love you, O Mu'adh!' I said: 'And I love you, O Messenger of Allah (ﷺ).' Then the Messenger of Allah (ﷺ) said: 'Never forget to say in every prayer: Rabbi a'inni 'ala dhikrika wa shukrika wa husni 'ibadatik (My Lord, help me to remember You, give thanks to You and worship You well)
Source
Sunan an-Nasā'ī · 1303
- Abu Ghuddah: Sahih
- Al-Albani: Sahih
- Zubair Ali Zai: Sahih