The Lord Jesus Christ says in effect, ‘You can read for yourself; what is written in the law?’, and the man summarizes the law perfectly. He doesn't go through all the commandments, and all the ordinances and the ritual requirements; that would take too long.
All of us know in our hearts that we owe God our obedience. The mistake we make is to think we can ever do this. Would we dare to quote the law with such confidence if we saw clearly how far short of it we fall. This lawyer has not minimised the wholehearted response that God requires. Does he think he can ever live up[ to that – ‘with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind’? We need to search our own hearts, our attitudes, our motives, our goals.