“False ideas are the greatest obstacles to the reception of the gospel” (J. Gresham Machen).
It is very true that false presuppositions of men and women are typically the biggest barriers to their reception of the Gospel of Jesus Christ.
If you hold the idea that evolution is true it typically follows that you disbelief in the Bible. If you disbelief the Bible, then you typically disbelieve the gospel message as a whole. Or else you disbelieve in God altogether and also conclude the gospel message is null and void.
If you believe that you’re a good person you will typically reject the gospel on the grounds that you aren’t someone in need of salvation; and neither is anyone for that matter because everyone goes to heaven in the end anyways. This also follows from the presupposition that God is a God who would never condemn anyone.
And then there are some who believe that they are such horrible people that there is no such thing as redemption for them, even if salvation does exist.
How you view the world, yourself, other people, and God will color how you will view the gospel message.
The problem with presuppositions is that often they are not founded in truth. As we discussed last week and the week before, evolution does still have a lot of questions to answer. If you have ever lied, cheated, stolen, swore, or done anything else against another human being you are not a good person. If God would never condemn anyone for their sin then he is not a just God. Likewise if there are people who God is unable to save based on their wretchedness, God cannot then be just either. If God is not just then he is not perfect, and an imperfect deity is no God at all.
But if the Bible can be trusted, if man is sinful, but if man can also be redeemed, and if God is just, that changes everything. Suddenly the gospel comes into focus, and salvation is at hand.