James 1:18

God does good things and all good and perfect gifts are from him. What is one thing he has done? Well, he birthed us by the word of truth. This birthing or bringing us forth is his saving or predestining us for saving. It is not merely birthing us to life, because that wouldn't necessarily need to be "by the word of truth". Instead, this is the saving work that he did, which is of his own free will. He chose to save us and this that he chose to do was certainly not a bad thing.

The reason for what he did was so that we would be a kind of firstfruits of his creatures. I think firstfruits in the Old Testament referred to the first and best of something, which was typically offered to God. You want to give God your best, so you give him the first of your crop and the best of your crop. I think the New Testament seems to use the term "firstfruits" to refer to Christ or those save through Christ. This is what he did for us and what a joy it is to be his best and his firstfruits in a way.