How do we know that conversion is necessary for salvation?

The Lord Jesus emphasized in Matthew 18:3 that except one be converted, they cannot enter the kingdom of heaven. This highlights the role of conversion as a necessary response to regeneration. While regeneration, or being born again, is a once-for-all event, conversion is a continuous process that demonstrates the evidence of true regeneration. Without the inner change of mind and heart, a person cannot claim to be a child of God, thus affirming the importance of conversion as crucial for salvation.