Dear sriram It is true that the following slokah is from Ishavasyopanishath; "Hiranmayena patrena sathyasyapihitam! tattvam Pushan apvrunu sathyadhatmaya drstaye!! But,it is not as what you have wriiten as below: Dhiranmayena patrena sathyasapihitam mukham! tattvam pushan apavrunu sathyadharmaya drstaye!! N.Srikanta.