Charles Ellicott Commentary Leviticus 7:13

"With cakes of leavened bread he shall offer his oblation with the sacrifice of his peace-offerings for thanksgiving." — Leviticus 7:13 (ASV)

Besides the cakes. —That is, the thirty unleavened cakes which were made of half of the quantity of the flour brought by the offerer, as described in the previous verse, the ten leavened cakes made of the other half of the flour are to be brought. These all had to be baked before the victim was slaughtered. The only other occasion when leavened bread formed part of the offering was on Pentecost (Leviticus 23:17); but no portion of it was burnt on the altar as a memorial, for leaven was forbidden to be on the altar. (See Leviticus 2:11-12.)