what does the bible say?
There are two major interpretations of Romans 4:17 where it says that God calls into being things that were not. The first is a reference to God creating ex nihilo (out of nothing). Scripture as a whole teaches that God created out of nothing (Hebrews 11:3), and thus, such an interpretation is biblically sound. However, it is difficult to connect that interpretation with the immediate context of God’s promise to Abraham (Romans 4:16–18). Still, it is possible that Paul was proving his point by reminding the reader that God can create life from nothing, for example, by giving an elderly couple a child (Romans 4:19).
The other interpretation understands it to mean: “the things that do not yet exist as though they already do” (NET). In this view, Paul is saying that God speaks of future realities as if they already exist because He will bring them about. That appears to fit the context better. He could say that Abraham was the father of many nations despite his wife being barren because God was speaking about what He would do (Romans 4:19).
In either case, the contextual point is that God’s promises will be accomplished. It is by believing them that faith is credited as righteousness (Romans 4:20–21). Our salvation also hangs on a promise. When we believe in Jesus by faith, we trust that He who brings into being what is not will surely fulfill His promise of eternal life through Christ.