We live in a world in which sometimes we may be confused about the things that we need to do. As human beings, we live in a specific time and place, and that determinates many obligations that we have as a citizen.
Because we are believers, we are called the best citizens and we fulfill all our obligations, all those that do not contradict our conscience. Jesus is very clear in that aspect: there are things that belong to Caesar and things that belong to God. Justice consists in giving to each one what belongs to them.
It is a big distinction in what belongs to Caesar (Government-nation) and what belongs to God.
Taxes, obligations of service, respect for those in government, etc. is part of what Jesus said about given to Caesar what belongs to Caesar. Our government, our nation, can ask things from us. We may give things that we possess, as for example to work, to pay taxes and to become responsible citizens, and these things are necessary for the good of the society that we live in.
But what belongs to God, is ourselves. We belong to God. We are His. To Him belongs not what we possess but who we are. This is the big difference.
This fact is based fundamentally in what each one of them can give us in return. The government can provide us with things that we need to live, protection, security… but like the government itself, those things will not last forever. God, in the other hand, has given us the world in which we live, and our lives. He gives us things that last forever, the promise of eternal life and perpetual happiness. These promises are more than what anyone can promise.
One other amazing thing in the gospel is something that maybe could pass unnoticed: Jesus asked: “Whose image is this and whose inscription?” They replied, “Caesar’s.” Think of this as the image of the world. But we carry the image of God. We were created on his own image, and because of that we belong to Him.
It could be that sometimes we may forget that we are the image of God, we may hide it, or cover it, but we cannot change it. That is who we are, and the consequence is indicated in the gospel “we belong to God”, and we need to him what belongs to Him.