One "small" problem with this quote.  It's attributed to a Letter Adams is said to have written in 1780.  Why is that important?  Well, if you go to the website which makes that attribution (click on the link above), you'll find that the Letter refers to the "Constitution" having been the product of a "Convention".  The problem is he's NOT talking about the U.S. Constitution, the convention for which didn't meet until 1787, and which wasn't ratified until 1789, LONG AFTER THE LETTER IS SUPPOSED TO HAVE BEEN WRITTEN!

Since the Letter also talks about limiting the power of the GOVERNOR, it's probable Adams was talking about the Massachusetts STATE Constitution.  Which, of course, begs the question: why is this quote doing on a website named "The Federalist Papers", since this has NOTHING to do with said Papers, or their subject (the U.S. Constitution)!

P.S. — It's also good to realize that not everything Adams wrote should be treated as "gospel".  For one thing, as his correspondence with Jefferson makes clear, he was adamantly opposed to the kind of Theology associated today with "right-wing" Christians.  On the other hand, he also opposed disestablishing the Congregationalist Church in his State (which was the "official" church there).  In fact, he "predicted" that the Solar System would be rearranged before that happened.  Events didn't work out that way!