In the Gospel passage this weekend, those trying to trap Jesus admit, "We know you are a truthful man … is it lawful to pay the census tax to Caesar?" Jesus' response was not focused on external law, but on what was going on in their own hearts.
He asked them to show him the coin that pays the tax. They handed him one. They weren't supposed to be in possession of one! They were trying to trap Jesus, but he's the one who caught them in something illegal according to their own law.
It's always good to invite God to examine our motives behind all we do and say. God sees through any smoke screens, and sees what's "in our pockets." We might as well be aboveboard and straightforward, and forget about any attempt to fool God into thinking that we're living perfectly. We don't have to worry about making a good impression on God. All we need to do is to speak and act truthfully, sincerely, and transparently.
A good prayer for us might be, 'Lord, show me your ways, and help me live by them."