Think about it this way:
You go swimming at the beach and a tidal wave sucks you under. You swim frantically for the surface, but you are so turned around that you can't tell which way is up.
Just when you fear the worst, someone grabs onto you and pulls you towards them. You follow in the same direction, knowing someone must be trying to rescue you. To your amazement, you actually find the surface and the next thing you remember is waking up on the sand, staring up at a group of people who look worried and frantic.
You're in shock, still unsure if this is all real and you really are still alive. People start asking you questions and telling you different things, but you're okay and you have this deep urge within you to find your savior and thank them. As you search around and ask who it was, you find out the truth.
There was a man who saw you drowning and dove in the waters to save you. He couldn't find you at first and he knew if he looked further he would have to make a choice. He had to risk his own life to save you. It was an easy decision and he dove in even further, searching until he finally found you. When he grabbed onto you, it took the rest of his strength to pull and push you in the right direction. He got you out, but didn't make it himself. He gave his life for you. He died so that you can live.
Imagine how thankful you would be and how much you'd long to bless him. You may think you know where this is going, but this is not a metaphor for the Christian life. Jesus didn't just give His life to save ours. It was so much bigger than that.
Think about it this way:
You wake up today and something smells wrong with the air around you. You walk out of your house to try and escape it, but it's the same. Some other people notice it too, but many don't seem to mind. Then you realize what it's like. It feels the same as when you were being pulled in that undercurrent. It feels like you're drowning.
You're confused, wondering how this suddenly happened and how you will survive. A panic sets in and that bad feeling escalates. You're thinking of where to go for help or who to ask, but everything you think of just sounds crazy. It feels like you're surrounded by water and yet on land. You can't breathe because you don't have life in you. For the first time, you became conscious to the same reality of so many others. We are dead and yet we walk around and breathe all the same.
How does Jesus rescue us? It's as if we're fish living out of water, desperate to connect to our life source and yet we don't have the lungs to do it. Jesus gives us gills to breathe underwater. Before you never noticed, but with a new revelation and a new set of gills, you can breathe in life from God, your source of life, for the first time. Now everything that you used to breathe in before tastes like death. It's a reverse metamorphosis, like a frog becoming a tadpole again. Everything goes back to the beginning and peace is established with God.
You're grateful again, wanting to thank the one who saved you and bless him. And then you remember all the other people who are still trying to breathe underwater with lungs. You found the truth and it set you free and you know the answer for them too. They need be become a new creation. They need gills to breathe underwater and it will change everything about them. They need to be connected to the source of life, but it's only through Jesus that it's possible.
This is why we're so persistent to share with others. It's because we found life in the Son of God and we long for everyone to receive the same hope of the eternal glory only found in Jesus Christ.