The question that the scribe asked Jesus was one that was a living issue in Jewish thought and discussion. It was often a matter of debate in the rabbinic schools. "Which commandment is the first of all?"
Instead of falling into old cliche and petty discussions Jesus, rises above them and reveals the radicalness of the first commandment. He quotes the beginning of the daily prayer of the Jews (Dt. 6:4-5) and concretizes it in the second commandment (Lev. 19:18). These two great commandments are well known. But Jesus combined them as one Law. For Him love of neighbour arises out of one's love for God. The one flows directly and necessarily from the other.
Jesus Himself showed in His life and death the quality of this two-fold love. His love for God motivated His total dedication to His mission; His love for humankind was that of the one who had come to serve and lay down His life for humankind.
Often it is much easier for us to say that we love God. The difficulty lies, however, in manifesting this love towards those around us including non-Christians. This is our challenge as Christians.
Lord, grant me a more complete participation in Your great love.