One must not rely on appearances, for even if someone appears blameless one never knows what is in his mind. The rule to remember is this: If someone refuses to benefit from the property of others – and needless to say from stolen property – and if he deals with others in good faith, then he is undoubtedly upright and honest.
But if he kisses his tefillin while he prays but does not deal with others in good faith, then one must stay as far away from him as possible. For the main test in which fear of Heaven and righteousness are put to the test is with regards to money. Whoever stands firm in his righteousness in monetary matters can be considered truly righteous.
(Kav HaYashar #52)