Jamieson, Fausset and Brown on Song of Solomon 7:2

2. navel--rather, "girdle-clasp," called from the part of the person underneath. The "shoes" (So 7:1) prove that dress is throughout presupposed on all parts where it is usually worn. She is "a bride adorned for her husband"; the "uncomely parts," being most adorned (1Co 12:23). The girdle-clasp was adorned with red rubies resembling the "round goblet" (crater or mixer) of spice-mixed wine (not "liquor," So 8:2; Is 5:22). The wine of the "New Testament in His blood" (Lu 22:20). The spiritual exhilaration by it was mistaken for that caused by new wine (Ac 2:13-17; Ep 5:18).

belly--that is, the vesture on it. As in Psa 45:13, 14, gold and needlework compose the bride's attire, so golden-colored "wheat" and white "lilies" here. The ripe grain, in token of harvest joy, used to be decorated with lilies; so the accumulated spiritual food (Joh 6:35; 12:24), free from chaff, not fenced with thorns, but made attractive by lilies ("believers," So 2:2; Ac 2:46, 47; 5:13, 14, in common partaking of it). Associated with the exhilarating wine cup (Zec 9:17), as here.