Responsibility, Mandate, or Both?

In a eulogy at his father's funeral, Ron Reagan -- son of the late President Ronald Reagan -- explained that his father's faith was a personal one, and that it had an effect on his presidency. Here's how Ron explained it:

"...after he was shot and nearly killed early in his presidency he came to believe that God had spared him in order that he might do good. But he accepted that as a responsibility, not a mandate. And there is a profound difference."

Responsibility vs. Mandate
Is there a difference? The Greatest Commandment and the 2nd Greatest Commandment and the Great Commission -- are these our responsibility, or also our mandate, or some combination?

Ephesians 2:10 For we are God's workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do.