The famous ethics work of the Ramchal, Mesilat Yesharim starts off the first chapter:
"The foundation of piety and the root of flawless service [of G-d] is for a man to clarify and come to realize as truth what is his obligation (chovato) in his world and to what he needs to direct his gaze and his aspiration in all that he toils all the days of his life"
and likewise in chapter 4
But that which, in particular, brings one to watchfulness is contemplation on the severity of the service which a man is obligated in and the depth of judgment incurred for it.
What is this "obligation" the Ramchal is referring to? Is it a moral duty such as gratitude to God or is it something else.
Looking for a source from other works of the Ramchal which explains this more.