This is the basic message of the Gospel of John 30.31. It is repeated over and over so we know it is very important. But what does he mean by "believing". Does he mean being baptized, attending church, being born again, reading the Bible, doing good works or just having hope? And what does he mean by "life"? Is he talking about physical life or spiritual life? How do we know if we have this "life"?
First, what does the writer of John mean by "believing"?
A friend was visiting and we got into an interesting discussion of the spiritual life of some family members. The various members of this family illustrate different interpretations of "believing". One is mean and selfish yet goes to church, prays and reads his Bible regularly. Another is kind, selfless, humble and rarely goes to church. Most have gone through a "born again" experience. Some attend a church others do not. These are all the children of Christian Missionaries so we know they have heard the story, had Bible teaching and been encouraged to believe. The big question is who is really saved by their believing? What are the signs of a believer?
Believing assumes knowing
The Bible teaches over and over that you cannot just be a good person and expect to have eternal spiritual life. There must first be the step of knowing about Jesus. The first sign that someone may be a believer is a thirst for Bible knowledge. This can come from daily Bible reading, formal courses, Bible Study groups or attending a church where there is Biblical preaching. My own experience of being an Anglican for 35 years before I personally read the Bible and became a much more serious believer is not unusual.
Believing is a response to 'knowing'.
Believing is our response to hearing or knowing the Good News of salvation in Jesus. Real believing leads to choices and actions. There is a wonderful story of a tightrope walker who set up a tightrope above Niagara Falls. He asked if people believed he could walk across and back. They could, so he did. Then he asked if they believed he could push a wheelbarrow across and back. They did, so he did it. Then he asked if they believed he could do it with a person in the wheelbarrow. They said they believed he could - but when he asked who would go first nobody volunteered. There is a wonderful prayer “Lord I believe, help my unbelief. If we really believe we are ready to respond and take risks. Some of the risky responses that would indicate we really believe might be seeking out Christian fellowship, attending church regularly, being part of a Bible Study group, sharing personal experiences of healing and self-sacrificial acts of love in the community
What does the Gospel writer mean by "have life"?
He is clearly not talking about physical life. He is talking about what we call "spiritual life". In the Gospel story of Jesus suddenly appearing, walking through locked doors and yet having a 'touchable' body; we are given a description of a resurrection body that seems to be both material and immaterial. This is a contradiction of logic as we understand it. Rather than getting sidetracked on this issue, it is more helpful to accept what the Bible says and learn what we can. The readings talk about 'the Holy One not seeing decay' when Peter quotes from Psalm 16. If we remember that we are still talking about the metaphysical world and the Resurrection is a dramatic example of this, we can move forward.
The 'holy one' is different.
Our spiritual life is to be holy - as opposed to unholy. This process begins with cleansing as we are washed with the waters of repentance and forgiveness in our Baptism. The point is that each time we go through little deaths to our selfish or sinful nature; we are raised to a deeper and richer spiritual life. This is not just a yes or no thing - as some evangelicals preach. It is a lifelong process that transforms us into holy people dependent on the shed blood of Jesus. We know we have this spiritual life as we experience feelings of love, joy and peace with God through believing in Jesus. The life we have is the alive feeling we have each day as we look forward to full resurrection life after our death.
Belief is a challenge
There is no easy path to this spiritual life. We have to find our way through all the false teachings along the way. The most common false teachings are universalism (everyone is saved so Jesus doesn't matter), sacramentalism (Baptism / being born again is all you need or only those in communion with our church are saved) and works (if you are a good person God has to let you into heaven). Many of the people who think of themselves as believing Christians have been deceived and confused by these false teachings. They may not be what the writer of the Gospel would consider "believing". We easily forget that there is an enemy whose sole purpose is to deceive us and confuse us in our spiritual life. I joke about 'quality control' but it is actually deadly serious.
Belief is an attitude of the heart
We all know people in our families who may not have a resurrection life. The Apostle Peter warns us that we will have "…to suffer grief in all kinds of trials." (1 Peter 1.6). The Good News is that this focuses us, challenges us and strengthens us as we go through the life-changing process of discerning the truth for ourselves by reading the Bible, prayer, self-examination, confession, thanksgiving and receiving the gifts of the Holy Spirit.
In the end belief is an attitude of the heart that no human can judge.