In which case, they didn't keep it "blamelessly," which is what you claimed. "Thou shalt love the Lord thy God with thy whole heart and with thy whole soul and with thy whole mind and with thy whole strength" is part of the Law too.
Philippians 3:4b-6 If anyone else thinks he has reason for confidence in the flesh, I have more: circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; as to the law, a Pharisee; as to zeal, a persecutor of the church; as to righteousness under the law, blameless.
Are you going to tell us now that Paul lied?
Has any man (other than Christ) kept THAT law?