Deuteronomy 20:6
And what man is he that hath planted a vineyard, and hath not yet eaten of it? let him also go and return unto his house, lest he die in the battle, and another man eat of it.
Cross-reference
Deuteronomy 28:30 lists as a curse the exact outcome the exemption prevents—planting a vineyard but not enjoying its fruit.
Leviticus 19:23-25 provides the law that fruit from a newly planted vineyard cannot be eaten until the fifth year—explaining why a man might not yet have used its fruit.
Isaiah 65:22 promises that planters will not have others eat their fruit—a direct reversal of the fear motivating the exemption here.
Jeremiah 31:5 promises that planters will enjoy their fruit—directly reversing the scenario in Deuteronomy 20:6 where another might use it.
Zephaniah 1:13 describes as judgment the very outcome the exemption seeks to avoid—planting vineyards but not drinking wine.
1 Corinthians 9:7 applies the same principle—who plants a vineyard and does not eat its fruit?—to argue for supporting gospel workers.