1 Corinthians 10:31
1 Corinthians 10:3131So whether you eat or drink or whatever you do, do it all to the glory of God.
The Watchtower cites 10:31 as permission for "wholesome family gatherings" at times other than birthdays, Christmas, Easter, or other days that fall under the organisation's extrabiblical bans. Reasoning From the Scriptures deploys the verse to show that Jehovah's Witnesses are "not opposed to celebrations as such, only to birthdays" and similar dates — the verse becomes a licensing principle for all eating/drinking activity, provided it is not on a forbidden day.
Paul's principle in 10:31 is broader than "do anything except the organisation's banned days." "Do all for the glory of God" is the positive umbrella under which Christian liberty on matters of indifference sits — the very liberty names specifically for days observed or not observed. The Watchtower uses 10:31 to license gatherings it approves while simultaneously overriding , which grants exactly that liberty to the Christians the organisation forbids. At the door: "Paul in 10:31 permits all eating and drinking for God's glory. Romans 14 names days specifically. If a Christian celebrates a birthday in thanksgiving to Jehovah, Paul's own principle permits it. The Watchtower's rule overrides Paul's liberty, not the other way around."