Islamic calligraphy وَقُل رَّبِّ ارْحَمْهُمَا كَمَا رَبَّيَانِي صَغِيرًا And, out of kindness, lower to them the wing of humility, and say: "My Lord! bestow on them thy Mercy even as they cherished me in childhood." Al-Israa
ربكم اعلم بكم Which means Lord, I know you. One should know what befits God and what does not befit God. That is to clearn Allaah from all imperfection and attribute to Him all the Absolute proper perfection that befits Him. The Exalted and the Glorified.