The Apostle James is talking about how OTHERS see our faith, how that a genuine faith WILL show by the fruit it bears. That is why James repeats phrases like "you see" and "seest thou". Man looks on the outward appearance, God looks at the heart. We are saved by grace through faith, alone, but it is a faith that is not alone. The fruit genuine faith bears does NOT contribute to our salvation, because our salvation is NOT by works - we don't earn, deserve or merit eternal life - it is ALL by grace.
So, even before the law, after the law, after Christ came the first time, before and after He returns again, it is ALWAYS by grace that God saves us. The sheep did the courageous and right things during the Tribulation because they WERE sheep already. The "goats" were always goats and their actions showed it. Someone helping the Jews during the Tribulation did not turn a goat into a sheep, it just demonstrated that he/she really was a sheep.