Does anyone know of any quotes that support that John Proctor as hard working? I already have this one: " I labor the earth from dawn of day to...

The quote identified is a fairly good one.  I would add to
it with a couple that reflect the willingness to take on additional burden and challenge
and not acquiesce to it.  For example, when he is ready to reveal the affair in order to
stop Abigail from her desire to corrupt more with her accusations, he says, "We will
slide together into our pit."  This reflects a willingness to avoid the easy path and
work to gain redemption.  There is nothing in Proctor's character as he evolves
throughout the play to reflect that he is seeking shortcuts.  His "steady manner" is
brought out through the resolve in trying to bring truth to a world where it is
noticeably absent.  This hard working nature is seen in his declaration of why his name
and reputation become so important to him.  When he says that everything else is gone
and all he wishes to have is his name, "Because it is my name," it reveals a desire to
not avoid work and labor, and accept the fact that what is worth preserving is worth the
commitment and struggle that is demanded by it.