Make up your mind, Samuel! Does God repent or not? In one chapter (1Samuel 15) we read that God tells Samuel He has repented (v11), and then Samuel says that God will not repent (v29), so which is it?
Now before answering the problem directly I think we need to say something about how to proceed with a challenge of this kind. Any fair-minded person will acknowledge that the writer of 1Samuel was not an idiot, and we can't conceive that the writer wrote verse 29 forgetting that he was contradicting what he wrote in v11. It is therefore evident that the writer saw no contradiction, and so, if we see a contradiction, it's obvious that we are not getting the intent of the author and we are misunderstanding his meaning.
Fair enough, so how do we square this? The answer is found in seeing the contexts in which God repents, and the reasons for the repentance. God "repents" when there is a change in the attitude or actions of men, so God says He is going to do such a thing (e.g. bless or judge), but the people to whom or about whom He speaks change their behaviour or attitude to Him (for good or evil), that then leads to God changing the manner in which He acts towards them. Consider this, the Bible says the person who sins will perish (Romans 2 v 12), but it also says that the person who believes in Christ won't perish (John 3 v 16), so we can state it like this, if we repent then God will repent.
However, when we read that God doesn't repent, what it means is that God doesn't just change His mind - He doesn't think about things and discover a better way of doing things, or reflect on His actions and decide He had been wrong. We often do that, we realise the way we had been going about something was wrong, ineffective or inefficient, and so we adjust - the repentance is based on us seeing something wrong in ourselves - in that sense God never repents. He never has to change His mind and actions based on His behaviour, but He will change His actions towards us based on our behaviour. If there's no change in our behaviour there will be no change in His.
To put this in a very relevant context, if you don't change your attitude and bow the knee to His Son seeking mercy and forgiveness then God will not change His attitude or rescind His promise - you'll perish, but if you do repent then the danger and distance is removed.
