In Acts 7 Stephen preaches to those “who received the law as delivered by angels and did not keep it.”

What does this mean? Did they try real hard but fail to measure up? Did they struggle to keep the law but find it was too difficult? Did they find that the law demanded absolutely perfect obedience without offering the forgiveness of sins, so that it was impossible to keep?

No.

They hated it and did not want to keep it and rejected and killed those who spoke of it on God’s behalf:

“You stiff-necked people, uncircumcised in heart and ears, you always resist the Holy Spirit. As your fathers did, so do you. Which of the prophets did your fathers not persecute? And they killed those who announced beforehand the coming of the Righteous One, whom you have now betrayed and murdered, you who received the law as delivered by angels and did not keep it.”