He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things? (ESV)
The love of God, our Heavenly Father, is beyond extravagant. As Paul has made clear in the opening chapters of the book of Romans every inclination of man's heart was pure rebellion to God. What is God's response? Instead of obliterating us off the face of the planet He provides his own son as a sacrifice for our sins. We were completely undeserving. He was completely loving.
The context of this verse is in the midst of a discussion of the righteousness of God that we have received as a free gift. We are no longer bound to the Law which we could never fulfill. Christ not only forgives our sin, but he also fulfilled the entire Law for us by living out a perfect life. Everything we need he has given.
Now that we understand the context it will help us to understand the rest of this verse. "How will he not also with him graciously give us all things?" Our selfish hearts would love for that to mean that God will give us financial security, a free pass when it comes to suffering, physical health and constant healing, and any other thing that we can think of to demand of God. Is that right?
That is not at all what Paul is suggesting. Paul himself struggled with constant persecutions and ailments. God will give to us what is needed (all things) for or walk with him! Consider Peter's words in 2 Peter 1:3: "His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, (ESV)"
All things are for God's glory. The purchase of your salvation glorifies God. Your life is to glorify God. Everything you need to glorify God will be given to you. His great gift gives him the right to all the glory.