How does God assure believers of their eternal security?

In 2 Samuel 7:9, God reassures David of His continuous presence and support, a promise that extends to all believers. The theological foundation underlying this promise is God's faithfulness and the assurance that He will complete the work He begins in His people. As articulated in Philippians 1:6, 'He who began a good work in you will carry it on to completion.' This unwavering commitment from God reflects His sovereign grace, assuring believers that, despite their weaknesses and shortcomings, their salvation is secured in Christ, who does not abandon His own.