Revelation 17:14

Revelation 17:14 These will make war with the Lamb, and the Lamb will overcome them, for He is Lord of lords and King of kings; and they who are with Him, the called and chosen and faithful, will also overcome them.

one of the most crucial characteristics of those who were produced to be the overcomers by the overcoming Christ, is "faithfulness". we are not faithful and we have no faithfulness in ourselves. But God is faithful, and He is constituting Himself into us to produce faithfulness within us. When we are constituded with God, the very faithful One, we can and will become faithful, and we must be faithful to God.