In The Name of Allaah, The Most Merciful, The Bestower of Mercy
Abbaas Bin Abdul Muttalib (radiyallaahu-anhu) said that he heard Allaah’s Messenger (sallal-laahu-alayhi-wasallam) saying:
ذَاقَ طَعْمَ الإيمَانِ مَنْ رَضِيَ بِالله رَبّا وَ باْلإِسْلاَمِ دِيناً و بِمُحَمّدٍ رسولا
The one who is pleased that Allah is his lord and Islam is his religion and Muhammad is his messenger shall taste the sweetness of Imaan.
The meaning of the Hadeeth is that he does not seek [other than Allaah-The Most High [i.e. he is pleased with the fact that Allaah is his Lord and only true object of worship(1)]. He does not follow other than the path of Islaam and does not follow except that which is in agreement with Muhammad’s [sallal-laahu-alayhi-wasallam] Sharee’ah . There is no doubt that the one characterised with this, then indeed the sweetness of Imaan becomes pure in his heart and has tasted its sweetness. 
[Refs 1 & 3; Source: Imdaadul Muslim Bi-Sharh Mukhtasar Al-Mundhiri Li-Saheehi Muslim. Vol 1. Page: 170 By Shaikh Ubaid Al-Jaabiri (may Allaah preserve him) – Slightly paraphrased]; [Ref 2;-For more benefits from this hadeeth, see [مدارج السالكين- 2/171. By Imaam Ibnul Qayyim (rahimahullaah)