How do we know that the church existed in the Old Testament?

Paul refers to the church as the 'Israel of God' in Galatians 6:16, indicating that there has always been a called-out people who worship the true God. The evidence of the church in the Old Testament is seen through various assemblies, such as during the times of the patriarchs and in the wilderness. God's people were recognizable as they prayed, worshiped, and followed His commands, which highlights a consistent theme throughout scripture that the church is not limited to the New Testament but has roots in God's covenant people.