If Abraham had been saved by works, could he have boasted forever?
Yes—if Abraham had been saved by works, he could have boasted, and that boasting would continue a jillion years later. But boasting is excluded, not by the law of works, but by the law of faith, so salvation is without works.
Les explains that if Abraham had been saved by works, he could have boasted, and if he boasted then, he would still be boasting a jillion years from now. Heaven would be awful and boring if people had to stop every five seconds and hear everything others did to get there. Boasting is excluded, taken out of the way, not by the law of works but by the law of faith. Paul says faith plus nothing until we are saved; then works follow naturally, so no one can say, “I did this for my salvation.” We rest totally on what has been done on our behalf.