How does a person come to inherit eternal life? Interestingly Jesus has just privately explained to the disciples that it comes through the Father and the Son revealing.
To the expert in the law, Jesus says that eternal life comes through obeying the law. We know however that obeying the law is only possible with the above revelation. It seems this expert in the law may be such a person because his summary of the law – the commands of God – is to love God with all our person and love others as ourselves. We know from the gospels that Jesus himself has taught this.
But the character of loving others can only be understood as it is revealed by Jesus. Jesus’ parable of the good Samaritan shows that generally the religious leaders do not keep the law, while a Samaritan (an outsider, much like sinners and tax-collectors) does keep the law. Keeping the law is to behave like Jesus who also crosses social boundaries, bring healing and acts in mercy.
To have eternal life is to obey the law. To obey the law includes loving others. Loving others can only be understood by Jesus revealing his own mercy across boundaries – and this in turn requires us to emulate him. This eternal life comes through Jesus revealing himself and thus enabling us to keep the heart of the law. The context then shows that eternal life is not gained by simply being kind to others but by living out the revelation that comes to us from the father and the Son.