How do we know if someone is part of the true church?

Determining if someone is part of the true church is ultimately beyond human judgment, as 1 Samuel 16:7 states that God looks at the heart while humans see the outer appearance. The visible church contains both believers and non-believers, or 'tares' among 'wheat.' While we can observe behaviors and professions of faith, we must remember that true membership is confirmed by God alone, as Jesus emphasized in the parable. The presence of sin and unfaithfulness among attendees further complicates this evaluation, reiterating the need for personal introspection and reliance on God's ultimate assessment.