Why do Christians experience a struggle between the flesh and the spirit?

In Romans 7:14-25, Paul describes the intense internal battle between the believer's flesh, which is still corrupted by sin, and the new spirit born of God. The text illustrates the dichotomy that exists within a believer who has the Holy Spirit yet contends with a sinful nature. This ongoing conflict shows that while believers are freed from the law's penalty, they still grapple with temptation and sin. The struggle is a reminder of their dependence on God's grace and the necessity of spiritual growth through the Word and the Spirit to maintain faithfulness amid trials.