Even the most religious Jews believed the kingdom of God would manifest as an earthly kingdom. Consequently, my guess is they believed the Roman Empire’s subjugation of Israel was an obstacle to the realization of the promised kingdom.
The requirement that Israelites pay taxes to this pagan nation that was, seemingly, preventing Israel from fulfilling its prophesied destiny would have been particularly offensive.
Their question to Jesus was intended to put Him on the horns of a dilemma: by denying their religiously-inspired nationalism or taking a publicly rebellious attitude toward the Roman Empire.
Jesus’s answer is remarkable. “Whose likeness do you see on the denarius? . . . Then render to Caesar the things that are Caesar’s and to God the things that are God’s.” Luke 20:20-26.
The image of Tiberius Cesar appeared on the coin, but it is the image of God that is imprinted upon man. When it comes to changing the world, what you give to God is more important than what you give to the government.
That’s a good thing to remember in the midst of a presidential campaign. GS