I’ve heard many people say “non-believers need to see miracles, then they will believe”. I agree to some extent, but it is not absolute truth. See Jn.11:45-46 for instance.
“Therefore many of the Jews who had come to visit Mary, and had seen what Jesus did, believed in him. But some of them went to the Pharisees and told them what Jesus had done.”
The Jews saw the miracles Jesus did, MANY BELIEVED BUT SOME WENT TO COMPLAIN ABOUT JESUS (these ones obviously didn’t believe). Have you not met people who have experienced God’s miracles and power at work in their lives but still didn’t believe in Him or after believing for a short time, walked away from the Lord? I have. So what is it that could secure a man’s soul forever? It’s the grace of God essentially. However, having been saved by the grace of God does not mean we do nothing to grow in His grace. 2Pet.1:5-11 makes it clear…..
“For this very reason, MAKE EVERY EFFORT to ADD TO YOUR FAITH goodness; and to goodness, knowledge; and to knowledge, self-control; and to self-control, perseverance; and to perseverance, godliness; and to godliness, mutual affection; and to mutual affection, love. For if you possess these qualities IN INCREASING MEASURE, they will keep you from being ineffective and unproductive in your knowledge of our Lord Jesus Christ. But whoever does not have them is nearsighted and blind, forgetting that they have been cleansed from their past sins. Therefore, my brothers and sisters, MAKE EVERY EFFORT to CONFIRM your calling and election. For IF YOU DO THESE THINGS, you will never stumble, and you will receive a rich welcome into the eternal kingdom of our Lord and Savior Jesus Christ.”
2 Peter 1:5-11 NIV