Is this passage talking about salvation or about Christian experience?
The passage addresses salvation, not Christian experience. It contrasts trying to merit favor with God by works with the gospel: Christ died, was buried, shed His blood, and rose from the dead. When believed, God imputes His righteousness, not our own, to the believer, as He did when Abraham believed.
Les explains that this passage is not talking about Christian experience, Christian works, and all that, but about salvation. In verse 4, “to him that worketh” means trying to merit favor with God. If salvation were by works, the reward would not be reckoned of grace but of death, because it would put God in debt, and God will never owe any man anything, not even a righteous man like Abraham. Les says the human race still tries to say God owes it heaven because of what they have done, but He does not. The only remedy for our sin is the gospel: Christ died, was buried, shed His blood, and rose from the dead. When we believe it, just as God saw Abraham believe, God imputes His righteousness to us—none of our own, all of His.