Galatians 3:19-20 Part 1 of 2

Why, then, was the law given at all? It was added because of transgressions until the Seed to whom the promise referred had come. The law was given through angels and entrusted to a mediator. A mediator, however, implies more than one party; but God is one. 

It was added because of transgressions 
Romans 5:19-21  The acts of the flesh are obvious: sexual immorality, impurity and debauchery; idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.

until the Seed to whom the promise referred to had come 
Galatians 3:16  The promises were spoken to Abraham and to his seed. Scripture does not say "and to seeds," meaning many people, but "and to your seed," meaning one person, who is Christ.

The law was given through angels 
Deuteronomy 33:2  He [Moses] said: "The LORD came from Sinai and dawned over them from Seir; he shown forth from Mount Paran. He came with myriads of holy ones from the south, from his mountain slopes."
Acts 7:51-53  "You stiff-necked people! Your hearts and ears are still uncircumcised. You are just like your ancestors: You always resist the Holy Spirit! Was there ever a prophet your ancestors did not persecute? They even killed those who predicted the coming of the Righteous One. And now you have betrayed and murdered him--you who have received the law that was given through angels but have not obeyed it." 

and entrusted to a mediator 
Exodus 20:18-19  When the people saw the thunder and lightning and heard the trumpet and saw the mountain in smoke, they trembled with fear. They stayed at a distance and said to Moses, "Speak to us yourself and we will listen. But do not have God speak to us or we will die."
Deuteronomy 5:5  (At that time I [Moses] stood between the LORD and you to declare to you the word of the LORD, because you were afraid of the fire and did not go up the mountain.") And he said: "..."

[brackets are mine]

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