How do we know the doctrine of spiritual life is true?

The truth of spiritual life is rooted in Scripture, particularly in Jesus' teaching that one must be 'born again' to enter the kingdom of God (John 3:3). This new birth is essential for genuine communion with Christ. As 1 Peter emphasizes, tasting the goodness of God is intrinsically linked to possessing spiritual life, indicating a personal relationship that is vital for spiritual sustenance. The assurance that we have spiritual life comes from experiencing God's presence, comfort, and grace in our lives, which cannot be fully understood or engaged in without first being spiritually awakened by the Holy Spirit.