How do we know that walking in the light is essential for Christians?

1 John 1:7 teaches us the necessity of walking in the light through the statement, 'But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.' This indicates that genuine fellowship with God requires a life characterized by truth and holiness, reflecting God's light. If we claim to be in fellowship with Him yet walk in darkness, we demonstrate a lack of true understanding of His character. Walking in the light is thus essential for maintaining a right relationship with God, enabling the continuous cleansing through the blood of Christ, which assures believers of their salvation and empowers them to live righteously.