The Essence
Ar-Razzaaq is the Supreme Provider who sustains all creation. He provides physical sustenance like food and wealth, but also spiritual sustenance like faith, knowledge, and tranquility.
In the Quran
إِنَّ اللَّهَ هُوَ الرَّزَّاقُ ذُو الْقُوَّةِ الْمَتِينُ
"Indeed, it is Allah who is the [continual] Provider (Ar-Razzaaq), the firm possessor of strength. (Surah Ad-Dhariyat 51:58)"
In Your Duas
اللَّهُمَّ إِنِّي أَسْأَلُكَ عِلْمًا نَافِعًا وَرِزْقًا طَيِّبًا وَعَمَلاً مُتَقَبَّلاً
"O Allah, I ask You for beneficial knowledge, pure provision (rizq), and acceptable deeds."
— Sunan Ibn Majah 925