Were bread and wine ever associated together in Old Testament worship?
No. While bread was used in tabernacle worship, such as the table of showbread and wave offering, and wine was used in drink offerings poured out, bread and wine were never associated in combination throughout the Old Testament economy. Their combined symbolism belongs to the Lord's Supper in the age of grace.
Les explains that Melchizedek brought Abram bread and wine. Bread was certainly used in tabernacle worship, as with the table of showbread and the wave offering, which was a sheaf of grain. Wine was also used separately in drink offerings, poured out. Yet never in the Old Testament economy were bread and wine associated in combination. In the age of grace, however, bread and wine speak of the Lord's Supper, the communion table.