The case of the criminal crucified alongside Jesus is the most high-profile death bed / last-minute conversion to Christ in the Bible (Luke 23:39-43). This criminal had been an unbeliever in Christ only moments before his death (see Matthew 27:44). The criminal, however, repented at the last moment and acknowledged Jesus as the heavenly King. The Lord blessed him by saying, "Today you shall be with Me in Paradise."
Although the story of the criminal on the cross shows that last-minute conversions are possible, the Bible warns us to repent now rather than later. "Repent, for the kingdom of heaven is at hand," warned John the Baptist (Matthew 3:2). "Repent, for the kingdom of heaven is at hand," Jesus said, emphasising the importance of immediate repentance (Matthew 4:17).
The Bible warns us about the shortness of the human lifespan. "You are just a vapour that appears for a brief moment and then vanishes" (James 4:14). We are not told to think about converting someday, but to believe right now! "Do not harden your hearts today if you hear his voice" (Hebrews 3:7-8, 14; 4:7). Nobody knows how much time we have left in this life or what will happen to us when we die. We may die suddenly and unexpectedly, precluding a deathbed conversion. Today is the only reasonable time to repent and believe in Jesus Christ.
Many people die without having spent a significant amount of time on their death bed. Many people die suddenly and unexpectedly, with no chance to put their faith in Christ. According to 2 Corinthians 6:2, "I heard you in my favour, and I helped you on the day of salvation. I tell you, now is the day of salvation, now is the time of God's favour."