What does the Bible mean by God being long-suffering?

God's long-suffering nature is a testament to His great mercy and grace towards humanity. As highlighted in 2 Peter 3:9, the Lord is not slack concerning His promises but is patient, not wanting any of His elect to perish. This long-suffering allows for repentance, emphasizing God's desire for all His chosen to come to a knowledge of the truth. The apparent delay in Christ's return is not a sign of weakness but rather an expression of His divine grace, providing opportunity for sinners to turn to Him before the final judgment. Understanding God's long-suffering encourages believers to share the gospel actively, knowing that God's patience continues to open hearts to repentance.