Now the promises were made to Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, “And to your offspring,” who is Christ. This is what I mean: the law, which came 430 years afterward, does not annul a covenant previously ratified by God, so as to make the promise void. For if the inheritance comes by the law, it no longer comes by promise; but God gave it to Abraham by a promise.
Why then the law? It was added because of transgressions, until the offspring should come to whom the promise had been made, and it was put in place through angels by an intermediary. Now an intermediary implies more than one, but God is one.
Is the law then contrary to the promises of God? Certainly not! For if a law had been given that could give life, then righteousness would indeed be by the law. But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
The Gospel. St. Luke 10:23b-37 (ESV)
“Blessed are the eyes that see what you see! For I tell you that many prophets and kings desired to see what you see, and did not see it, and to hear what you hear, and did not hear it.”
And behold, a lawyer stood up to put him to the test, saying, “Teacher, what shall I do to inherit eternal life?” He said to him, “What is written in the Law? How do you read it?” And he answered, “You shall love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind, and your neighbor as yourself.” And he said to him, “You have answered correctly; do this, and you will live.”
But he, desiring to justify himself, said to Jesus, “And who is my neighbor?” Jesus replied, “A man was going down from Jerusalem to Jericho, and he fell among robbers, who stripped him and beat him and departed, leaving him half dead. Now by chance a priest was going down that road, and when he saw him he passed by on the other side. So likewise a Levite, when he came to the place and saw him, passed by on the other side. But a Samaritan, as he journeyed, came to where he was, and when he saw him, he had compassion. He went to him and bound up his wounds, pouring on oil and wine. Then he set him on his own animal and brought him to an inn and took care of him. And the next day he took out two denarii and gave them to the innkeeper, saying, ‘Take care of him, and whatever more you spend, I will repay you when I come back.’ Which of these three, do you think, proved to be a neighbor to the man who fell among the robbers?” He said, “The one who showed him mercy.” And Jesus said to him, “You go, and do likewise.”