In His answer, Christ goes beyond the question, and thus gives us to understand that He covers the whole subject involved therein.
Thus He tells which is the “great” commandment, and then imparts the additional information that this is the “first,” and that to the system there belongs another which is the “second;” and that this second is like unto the first; namely, “Thou shalt love thy neighbor as thyself;” that is,
it embraces the same great principle of love,
only giving it another direction.
In the first, our love is directed toward God;
in the second, our love is directed toward our neighbor.
And these two principles embrace the whole of the law of which He speaks; for if there had been a third, the logic of the situation would have compelled him to state it.
The duty of loving God, therefore, and loving our fellow men, is the subject which He treats in answering the lawyer’s question."
Uriah Smith