What does it mean to be 'in God' according to the Bible?

Being 'in God' speaks to the profound union that believers have with the Father and the Son, which is foundational to Christian identity and experience. This concept is intricately tied to the notion of fellowship and belonging in Christ. In 1 Thessalonians 1:1, Paul writes to the church that is 'in God the Father and in the Lord Jesus Christ,' emphasizing that their spiritual location transcends their earthly setting. This union denotes that believers are part of a new creation—all that once defined their identity is overshadowed by their relationship with God through Christ. Such intimacy leads to the experience of grace and peace that flows from this relationship, as affirmed in Romans 5:1-2, where having been justified by faith, believers now enjoy peace with God through Jesus Christ. Thus, being 'in God' shapes the believer's life, purpose, and hope.