How do we know losing our savour as Christians is serious?

Matthew 5:13 warns that if the salt has lost its savour, it is 'good for nothing' but to be cast out. This metaphor underscores the serious nature of a Christian's spiritual state when they stray from their relationship with Christ. When believers fail to walk in communion with God, their lives do not reflect the grace and truth of the gospel, rendering their witness ineffective. This condition not only affects their spiritual life but also diminishes their ability to impact others positively for the kingdom of God, putting them at risk of being disregarded by both God and the world.