What does the Bible say about the outward man perishing and the inward man being renewed?

In 2 Corinthians 4:16-18, the Apostle Paul emphasizes that although our outward self is subject to decay, the inward self experiences renewal each day. This highlights the profound truth of regeneration and spiritual growth in Christ, where believers, despite external afflictions and challenges, can find strength and rejuvenation through their relationship with God. This renewal is an ongoing process, driven by the Holy Spirit, which prepares believers for eternal glory that surpasses all temporal sufferings.