Q: Wherein is the moral law summarily comprehended?
A: The moral law is summarily comprehended in the ten commandments.

Matthew 19:17-19. And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments. He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness, Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself.

Westminster Project - See Matthew Henry Scriptural Catechism based on the method of the Assembly