The following is a part of Donald Trump's remarks on Vegas shooting.
In moments of tragedy and horror, America comes together as one -- and it always has. We call upon the bonds that unite us -- our faith, our family, and our shared values. We call upon the bonds of citizenship, the ties of community, and the comfort of our common humanity.
Does the idiom phrase 'call upon' here mean 'produce, utilize' or 'appeal to'?