Musar על בבא בתרא 176:14

Our Sages of blessed memory also said: "stealing from another person is worse than stealing from Temple property, for in the former, the word 'sin' precedes the word 'betrayal' [and the opposite in the latter]..."

I will not speak with respect to deception in the area of measurements for scripture explicitly states: "the abomination of the L-rd your G-d are all who do these" (Devarim 25:16). They further stated: "the punishment for dishonest weights and measures is worse than the punishment for illicit relations" (Bava Basra 88b) and "a wholesale dealer must wipe his measures clean once in thirty days..." (ibid 88a). Why all this? So that they do not unknowingly diminish in measure and he is not punished [for stealing from his customers due to negligence].