"It's a long, long line: a glimpse into eternity" refers to a Christian book by Bob Highlands III, exploring themes of the afterlife, what happens after death, and encountering God, often using allegorical language about a vast queue into the divine presence, contrasting fleeting earthly life with eternal existence. It's a spiritual narrative designed to offer insight into biblical truths and personal encounters with God's love and the promise of a heavenly realm.