How do we know Jesus' teachings about spiritual family are true?

Jesus emphasizes the nature of His kingdom as spiritual rather than earthly, highlighting that true kinship is found among those who do the will of the Father (Matthew 12:50). This radical shift redefines familial relationships, underscoring the eternal significance of the church as the body of believers. The relationships fostered in faith transcend biological ties, as seen in the words He spoke to Mary and the disciple, indicating a reorientation towards spiritual fellowship over natural bonds. Believers are thus part of a family united in Christ, transcending earthly norms.