Allāh’s Messenger (SAW) said, “A person who is content with Allāh as his Lord, Islām as his religion, and Muḥammad as his Prophet will taste the sweetness of faith.” (Muslim #56)
This ḥadīth encourages us to work towards achieving sweetness of faith and making it a quality intrinsic to us. This sweetness stems from that sublime sense of contentment and satisfaction coming from certainty in Allāh, certainty in His decree, and certainty in His wisdom, mercy and justice when governing creation. This in turn leads to quietude of heart when submitting to Allāh’s judgements and giving preference to what pleases Him.
The sweetness also derives from contentment with Islām which entails following it and rejecting all other religion and ways of life. Muslims are content and pleased with all of Allāh’s Prophets, but being content with Muḥammad (SAW) entails something additional which is to accept that, after the advent of Islām, only his path is valid and it is only his footsteps that we walk in.
When a person is content with these three, faith will permeate every fibre of his being, and he will relish obeying Allāh and the Messenger (SAW) sent by Him, without that obedience seeming onerous at all. The beauty of Allāh’s religion, Islām will settle in his very core.
Then Allāh’s servant will not seek another besides Allāh as lord, he will only ever walk the path of Islām, and will only do what agrees with the law of Muḥammad (SAW). He will be pleased with Allāh, His Messenger, and His religion.
(Qurtubī, al-Mufhim 1:210-211, ʿIyād, Ikmāl al-Muʿlim 1:270, Nawawī, Sharḥ Ṣaḥīḥ Muslim 2:3, Ṭībī, Sharḥu’l-Mishkāt 1:122)