"Ya Rabbi lakal hamdu kamaa yanbaghii lijalaali wajhika wa 'adhiimi sulthaanik"...

 

The complete phrase for this powerful remembrance is 

"Ya Rabbi lakal hamdu kamaa yanbaghii lijalaali wajhika wa 'adhiimi sulthaanik".

يَا رَبِّ لَـكَ الْحَـمْـدُ كَـمَـا يَـنْـبَـغِـيْ لِـجَـلَالِ وَجْـهِكَ وَعَـظِـيْـمِ سُــلْـطَـانِـكَ 

Meaning

"O my Lord, all praises be to You as it should be due to Your Might and the Greatness of Your Power."

("O Lord, to You belongs praise as befits the majesty of Your Face and the greatness of Your dominion.")

Significance and Virtue

The Story of the Angels: 

According to a narration 

(recorded in Sunan Ibn Majah), 

an angel or a servant of Allah recited these words. 

The two recording angels were unsure of how to measure and write down the immense reward for this specific praise, so they ascended to the heavens to ask Allah.

Direct Reward from Allah:

 Even though He already knows what is said, Allah asked them what the servant had uttered. 

When told, Allah commanded them to leave it unmeasured, stating:

 "Write it down just as My servant has uttered it until he meets Me, and I shall reward him for it Myself."

wallahu a'lam ..