"Now brothers, I want to remind you of the gospel I preached to you" (1 Corinthians 15:1)

Despite it being the "good, glad, and merry tidings that causeth the hard to sing and the feet to dance," the gospel of Christ is not the default mindset of human nature. It needs to be preached to the world, and to believers--repeatedly. For this reason, Christians ought to meet together regularly for mutual encouragement and 'reminding.'