Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
muslim:1667 – Muḥammad b. Rāfiʿ > ʿAbd al-Razzāq > Maʿmar > Hammām b. Munabbih > Hadhā Mā > Abū Hurayrah

It is good for a slave that he worships Allah well, and serves his master (well). It is good for him.  

مسلم:١٦٦٧ – وَحَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ حَدَّثَنَا عَبْدُ الرَّزَّاقِ حَدَّثَنَا مَعْمَرٌ عَنْ هَمَّامِ بْنِ مُنَبِّهٍ قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ

عَنْ رَسُولِ اللَّهِ ﷺ فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ قَالَ رَسُولُ اللَّهِ ﷺ نِعِمَّا لِلْمَمْلُوكِ أَنْ يُتَوَفَّى يُحْسِنُ عِبَادَةَ اللَّهِ وَصَحَابَةَ سَيِّدِهِ نِعِمَّا لَهُ  

See similar narrations below:

Collected by Aḥmad, Suyūṭī
ahmad:8233 –

[Machine] And the Messenger of Allah, ﷺ , said: "What a great blessing for a slave to be taken while in the good worship of Allah and the company of His Prophet, what a great blessing for him."  

أحمد:٨٢٣٣ –

وَقَالَ رَسُولُ اللهِ ﷺ نِعْمَّا لِلْمَمْلُوكِ أَنْ يُتَوَفَّى بِحُسْنِعِبَادَةِ اللهِ وَصَحَابَةِ سَيِّدِهِ نِعِمَّا لَهُ