In one town lived a poor, kind carpenter named Bhai Lalo, who shared his simple bread with Guru Nanak. Nearby lived a rich man, Malik Bhago, who made his money unfairly and threw grand feasts to show off.
Malik Bhago was offended that the Guru preferred plain bread to his fancy dishes. So Guru Nanak gently took Lalo's honest bread in one hand and Bhago's rich food in the other, and squeezed them.
From the poor man's honest bread flowed pure milk, but from the rich man's food dripped blood — for it had been earned by treating others unfairly. Everyone understood at once what the Guru meant.