My take: Two of the most important attributes in life that we can control are our attitude and action.
In this first statement we see the word ‘serve’. Is there not a better way to prosper than by truly being a most excellent servent?
But if we do it begrudgingly, our service loses its luster. Service without a smile is a downer so he says do it with gladness.
Then whom should we serve? 1st and foremost; the LORD! Then everyone else.
In the second statement, we see an important way to access the presence of God; by singing.
My prayer: LORD of all, I want to serve with gladness. Please forgive me for all the times I have done so with a selfish and inner focused heart and poor attitude. Help me to model Jesus; the ultimate servant.