"and your gifts": These are thank-offerings and peace-offerings. What does Scripture come to teach us? If (that it is forbidden) to eat a thank-offering and peace-offerings outside the wall, this can be derived a fortiori from ma'aser, viz.: If ma'aser, which is not liable for piggul (improper intention), and nothar (exceeding of a time limitation) and for (being eaten by one who is) tamei — if one eats of it outside the wall, he transgresses a negative commandment, then a thank-offering and peace-offering, which are liable for piggul and nothar and for tamei, how much more so does he transgress a negative commandment if he eats of it outside the wall!
The purpose of the verse, then, must be to teach us that if one eats a thank-offering and peace-offerings before the sprinkling of the blood (of the sacrifice) he transgresses a negative commandment.