Two things I will offer - firstly a page from a talk I've not quite finished preparing on Luke 3v1-21 for Bath CU next week:
Firstly, Don't trust in your background. John calls the people to repent saying - "Do not begin to say to yourselves 'we have Abraham as our Father'". The Jewish people are descendants of Abraham. Dangerously they assumed that physical relationship saved them. John says no. You're vipers, evil and deceiving. Don't think this way “For I tell you that out of these stones God can raise up children for Abraham”. God can and will miraculously raise up the kind of people he is looking for. Children of Abraham is Bible language for people who trust God like Abraham did, and you can read about that in the book of Genesis.And a secondly: Learn to read the Bible like 3 year old Isabel
We might think the same – perhaps you have Christian parents or have attended church meetings, prayed a prayer of commitment to Jesus at some point. Rejoice in that, but don't think that your past can save you. God comes and he will find a people for himself. He comes to us – what will he find? Viperous self-rescuers who trust in their religion and background. The axe awaits such people. Our only hope will be when our only hope is Jesus.
V16. Secondly, don't trust in your behaviour John has told people to change. People ask him, v10, what shall we do... He says, v11-14, change your way of living – be generous, act justly, be content. But, notice what he's doing. He says bear fruit in keeping with repentance. John Piper explains this:“this means that repenting is what happens inside us. Then this change leads to the fruits of new behaviour. Repentance is not the new deeds but the inward change that bears the fruit of new deeds. Jesus is demanding that we experience this inward change”There's a lie going round that those who live good lives are the people God loves. That Christians are good people. Two thousand years ago, in the 15th year of the reign of Tiberius Caesar, John the preacher showed that wasn't the case. People can't just change, we need God to grant us repentance. We're selfish, unjust and greedy and only by repentance can we change. John prepares the way by calling for repentance. But he's not the One. People even asked, v15 – are you the Christ, are you God's promised rescuer? And John said, v16, no – he comes next, he does more.
John gives external washing called baptism with water. The Christ who follows him, v16, will baptise with the Holy Spirit and with fire. The Christ will raise up children of Abraham by changing hearts. Raising up rocks to be children of Abraham. Rescuing rebels in the desert. Good behaviour can't save us – we need to bear fruit but we're dead unless he changes our hearts. What gloriously good news! No need to impress – a bath from John might clean you up a bit but the Christ comes to give you a new heart! You can't earn it, nor can you be too bad for it. Don't fake it, and don't despair. See that your only hope is when your only hope is Jesus.