What does it mean that the Law was an administration of death?
It means the Law held people in death, and believers are delivered from it. It belongs to the oldness of the letter, not the newness of spirit. Through believing the Gospel, believers now serve in the spiritual realm rather than returning to Law and legalism.
Les teaches that the Law was an administration of death and that believers are delivered from it, described as being dead wherein we were held. The Law belongs to the oldness of the letter, but believers now serve in newness of spirit. He asks how this happens and answers, "Believe the Gospel." In Galatians 3:3 he contrasts beginning in the Spirit by Paul's Gospel through faith plus nothing with trying to grow by the flesh. The flesh in the Galatian churches wanted legalism—Law—because it is part of the old Adamic nature to want to be under some kind of Law. Galatians 3:4 adds, "Have you suffered so many things in vain, if it be yet in vain?"