How can a sinful person be considered holy?

According to Scripture, all humans are sinful by nature, as expressed in Romans 3:10-12, where it states that none are righteous. However, believers are called 'holy brethren' because they are united with Christ who sanctifies them. Hebrews 2:11 explains that both Christ and those He sanctifies are one. This union means that believers share in His holiness. Furthermore, the work of the Holy Spirit in regeneration gives believers a holy nature, making them incapable of sin as highlighted in 1 John 3:9. Therefore, while believers may still struggle with sin, in God's sight, they are declared holy due to Christ's redemptive work.