Why is God's preserving grace important for Christians?

God's preserving grace is crucial for Christians as it provides them with assurance and comfort amidst their struggles. Knowing that their salvation is secured by God's power and not their performance allows believers to face doubts and challenges without fear of losing their salvation. The sustaining grace illustrates that the Christian life is a pilgrimage upheld by God's ongoing work, highlighting that He does not only save but continuously supports His children through sanctification. This assurance helps believers to trust in God's faithfulness, as seen in Hebrews 7:25 where it affirms that God saves to the uttermost.