The wave offering (tᵉnûpāh) is derived from a verb which means to move backwards and forwards. According to Ross (p.192), the offering was placed in the worshipper’s hands, and then the priest would place his hands beneath those of the worshipper. The offering would then be moved upward and downward, forward and backward, symbolizing its consecration in the sight of all.
30 His own hands shall bring the LORD’s food offerings. He shall bring the fat with the breast, that the breast may be waved as a wave offering before the LORD.