It is dangerous to take any sentence in isolation and consider it bereft of context, for that is how meaning and intent get distorted, but noteworthy in this sentence even in isolation from Paul's Letter to the Hebrews is the complete absence of any reference to God. Even the sentence that follows this refers to men, and not to God: "This is what the ancients were commended for."
To the obvious rebuttal that the Apostle Paul is speaking specifically about faith in God throughout the Epistle and thus there is no need to mention of God in this sentence, there is the counter that if Paul addresses a specific form of faith, it follows there must then be a general--generic--concept of faith. This general formulation of faith is what Paul gives us at the beginning of Chapter 11 of his Letter to the Hebrews. As Paul gives us a general formulation of faith, we may safely extract it from the surrounding text without doing violence to that text, and explore the nature of faith.