2 Now everyone is a soldier of this true God, and he who receives and worships Him in his inmost spirit, does not bring to His service dissimulation, or pretence, but earnest faith and devotion. And if, in fine, he does not attain to this, at least he ought not to give any countenance to the worship of idols and to profane ceremonies. For no one deceives God, to whom all things, even the hidden things of the heart, are manifest.
Source: Letters (New Advent)