The expression occurs but once in all the Bible, but the passage in question does not reveal the day of the week. It reads as follows: "I was in the Spirit on the Lord's day." Rev. 1:10. Now, according to God's Word, for this alone is authority upon this question, what day is the Lord's day? Three scriptures will answer this most conclusively: "If thou turn away thy foot from the Sabbath, from doing thy pleasure on My holy day." Isa. 58:13. "The seventh day is the Sabbath of the Lord thy God." Ex. 20:10. "The Son of Man is Lord also of the Sabbath." Mark 2:28. These texts conclusively show that the Lord's holy day is the Sabbath, and that the Sabbath is the seventh day, and that the seventh-day Sabbath is the day of which Jesus Christ is Lord. Therefore, according to the Lord's Word, the Lord's day is the seventh-day Sabbath. Could we ask clearer evidence?