…in days when life was smooth and easy, then people said how exciting it was to investigate truth and to examine it, and there were people who thought that was Christianity. It was to be a ‘seeker’, and you read literature and you compared this with that, and you said how marvellous it all was! But in a world like this one of the twentieth century you have no time for this, and thank God for that! We are in a world where black is black and white is white and that is in accordance with the New Testament teaching.
Christians are men and women who are certain, and John writes in order that these people may be absolutely sure. They were sure, but there were certain things that were not clear to them. That always seems to be the position of the Christian in this life and world. We can start with the truth which we believe by faith. Then it is attacked and we are shaken by various things but, thank God, these lessons are given to us to strengthen and establish us…. There are certain things that you and I should know. Christians have ceased to be seekers and enquirers; they are men and women who have ceased to doubt.…
But about what are we to have this certainty? Firstly, we are to be certain about ourselves. We know that we are of God. What is a Christian? Are Christians just people who pay a formal respect to God and to public worship? Are they just mechanically attached to a church? Do they just try to live a good life and to be a little bit better than others? Are they just philanthropists, people who believe in a certain amount of benevolence? They are all that, of course, but how infinitely more! Now, says John, we know this truth about ourselves as Christians. ‘We are of God'; by which he means nothing less than this: we are born of God; we are partakers of the divine nature; we have been born again; we have been born from above, we have been born of the Spirit, we are a new creation.
Martyn Lloyd-Jones, Fellowship with God p. 16-17