Mark 12:13-17 ASV

If Jesus would have said it was ok to pay taxes, the jewish people would have been upset because the Romans were taking huge taxes from everyone and the jewish people were not happy about it. If Jesus would have said it was ok not to pay taxes, he could have been arrested for going against Roman law.

So Jesus shows that God is above human rules and that God is supreme over everything. So sorry you can't trick Jesus.