How do you know when you are a Christian?

Happy Christmas

The day is easier to define - not necessarily accurate but at least it can be arbitarily set so that everyone can point to it and know when it a) is and b) is not.

Being a Christian is another matter all together. There is no easy yes/no definition from the Bible. Jesus discussed many aspects of following Him, yet no one clear 'this is how you do it and this is how you don't.'
Even worse He gave no clear way of recognising 'them'. Of course we can know them by their fruit and whether they are wearing wolf's clothing or not... but this is pretty much subjective. Everyone has their own benchmark for judging other's quality of spirituality.
The Catholic church havea good system where by you are born into the church and so it you can be sure you are a Christian by association of birth.

Do you?
Do you have to pray a prayer?
Do you have to make a confession with your mouth?
Do you have to believe with your heart?
Do you have to be baptized with water?
Do you have to be baptized in the Spirit?
Do you have to be re-born?
Do you have to do good works?
Do you have to sell all you have?
Do you have to tell someone you have become a Christian and attend a Sunday meeting and one weekday meeting?
Do you have to believe Jesus is the Son of God?
Do you have to believe Jesus' work on the Cross?
Do you have to renounce Satan and all his works?
Do you have to believe the Westminster confession or the Nicene creed?
Do you have to believe Creationism?

Like a mortgage?
Like the type of mortgage used by self-employed people: a 'self-certification mortgage', it must come down to:
'We are if we believe ourselves to be'

In the same way that the mortgage has inherent risk of not being able to back up in the long term what we said we could pay, we need to be able to back up in Christ what we have claimed.