Of course Paul is referring to faith in God, and in His Son Jesus Christ. To believe in Them, and in Their promises, requires a measure of faith.
To not believe in God, and to go so far as to deny His existence, that too requires a measure of faith — indeed, a tremendous measure of faith in nothing.
For that is what atheism is: Faith in nothing.
This could be rewritten from an atheist's point of view: "Through faith in nothing we understand that the worlds were framed by happenstance…."
The atheist has zero evidence that God did not create the world. Their faith is the "substance of things hoped for". What do they hope for? A God-less spontaneous creation. Their faith is also for them "the evidence of things not seen". What haven’t they seen? A God-less spontaneous creation. Atheists can theorize and extrapolate conclusions about the processes of creation, but they will never have a single shred of evidence that God does not exist, or that he was not in control of the creation.
I defy any atheist to provide evidence of the absence of God. It cannot be done.
Some atheists will cite the human condition, and the misery and suffering that exists in the world as evidence that God doesn't exist. That is not evidence. A God's purposes are not to be dictated by atheists or believers. Failure of a parent to protect their children from physical harm, or to force their children's behavior, doesn't mean the parent does not exist.
Many atheists will cite scientific theories (yes, these are indeed just theories) of the big bang, or of evolution, to justify their disbelief. These aren't evidence of no God. Even if they weren't theories, even if the big bang and evolution could be proven beyond any doubt, they still wouldn't prove that God doesn't exist, or that He had nothing to do with creation. Atheists can draw that conclusion if they so choose, but it is a faith-based conclusion.
Even if mankind were to develop the technology for instantaneous space travel, build millions of spacecraft, and spend thousands of years sending tens of millions of investigators throughout universe to search for God, failure to find Him would not prove He does not exist.
Of course, an atheist's inability to provide evidence of the absence of God is not evidence of the existence of God.
But that doesn't mean there is no evidence of God. I personally see a preponderance of evidence; evidence that may not be conclusive to an atheist, but evidence that easily leads myself and millions of others to the faith-based conclusion that there is a God.
First and foremost among the evidence I have for God are several private, sacred personal experiences that for me are irrefutable proofs of God. I'm not alone. I personally know several people I trust who have had similar, or even greater experiences. Indeed, countless people past and present have had such experiences.
For myself and many others, including many prominent scientists, philosophers and so-called intellectuals, the limited scientific understanding we have of the marvelous workings of the universe is one of the evidences of God.
It was for Albert Einstein:
Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible concatenations, there remains something subtle, intangible and inexplicable. Veneration for this force beyond anything that we can comprehend is my religion. To that extent I am, in point of fact, religious…. In view of such harmony in the cosmos which I, with my limited human mind, am able to recognise, there are yet people who say there is no God. But what makes me really angry is that they quote me for support of such views. [ref]
I cannot anyhow be contented to view this wonderful universe, and especially the nature of man, and to conclude that everything is the result of brute force. I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we may call chance. Not that this notion at all satisfies me. I feel most deeply that the whole subject is too profound for the human intellect. A dog might as well speculate on the mind of Newton. Let each man hope and believe what he can. Certainly I agree with you that my views are not at all necessarily atheistical. [ref]
What I don't support at all is the concerted effort by atheists to remove belief in God from public life and discourse. Why should faith in nothing trump faith in God? "Separation of church and state", they vehemently declare, refusing to concede the true meaning and historical context of the Constitutional protection of religious faith:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof [United States Constitution,First Amendment]
So why should atheism be treated any differently? It is, after all faith — a religious faith in nothing. Of course it shouldn't be treated differently! Congress should not pass laws favoring faith in nothing over faith in God, and Congress, the Courts, and government bureaucracies should not aid and abet atheists in their zealous attempts to silence those whose faith is in God.