House management is also an acceptable meaning of the word.
God has one manager working for Him at a time.
Moses was God's old appointed manager, as His chosen dispenser of Law.
Paul, His chosen dispenser of the Gospel of grace and of Christ according to the revealing of the secret, is still the manager because we're still in the dispensation of grace.
To seek to follow any aspect of the Law as a means of salvation or as a rule of life is to follow the old manager. It denies God's grace, telling Him you know better than He does how to manage your affairs.
If you understood the difference between the Old Covenant and New Covenant, and didn't deny the New Covenant, you wouldn't be so confused.
to the revealing of the secret
You're also very confused about Paul.
(Matt 13:35 ) ... I will utter things which have been kept secret from the foundation of the world.
Can you tell us some of the secrets Jesus revealed?