The Essence
Al-Waliyy is the Protective Friend, Ally, and Supporter of the believers. He guides them out of darkness into light, manages their affairs with love, and defends them against their enemies.
In the Quran
اللَّهُ وَلِيُّ الَّذِينَ آمَنُوا يُخْرِجُهُمْ مِنَ الظُّلُمَاتِ إِلَى النُّورِ
"Allah is the ally (Waliyy) of those who believe. He brings them out from darknesses into the light. (Surah Al-Baqarah 2:257)"
In Your Duas
أَنْتَ وَلِيِّي فِي الدُّنْيَا وَالْآخِرَةِ ۖ تَوَفَّنِي مُسْلِمًا وَأَلْحِقْنِي بِالصَّالِحِينَ
"You are my Protector (Waliyy) in this world and in the Hereafter. Cause me to die a Muslim and join me with the righteous."
— Quran, Surah Yusuf 12:101