לא תאפה חמץ, חלקם נתתי (צו – ו:י)

Rashi says: We learn from here that also the ‘שיריים’ – leftover from the Korban Mincha, is forbidden to be made chometz.

It can also be explained that ‘חמץ’ – alludes to גאוה – haughtiness – like chometz rises up big, and ‘שיריים’ – alludes to ענוה – humbleness – holding nothing of oneself.  The Torah wants to tell us that ‘leftovers of humility are a very worthy thing; however, one needs to be careful that this humility shouldn’t lead to ‘chometz’ – a person shouldn’t feel haughty with his humility.