> do you believe man goes to heaven through faith alone, or by faith and works that prove their faith?
To clarify, Protestants believe Sola Fide (justification by faith alone), but they also believe faith implies good works. The difference is that Catholics consider faith and works more independent entities. They believe works are another requirement to be saved, in addition to faith.
From Protestants' point of view, faith in Jesus Christ is the only requirement to be saved. At the same time, works are a great way to display someone's faith, as Jesus says:
> By this everyone will know that you are my disciples, if you love one another. — John 13:35 (NIV)
You might say "So, we can just believe in God and do any despicable things we want, then?" Not really. You couldn't say you love your spouse and at the same time keep hurting them, could you? Your actions would contradict your words, and no one would believe your words that you love your spouse.
Similarly, Christians who realized how great the love and sacrifice that God gave to pay their sins are will (or at least try to) live accordingly. They do good things, not to be saved, but because they have already been saved and they want to show their gratitude through their works and glorify God. Jesus says:
> In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven. — Matthew 5:16 (NIV)
This is the unique distinction between Christianity and other religions. If human beings could by their own effort save themselves from the wages of sins, Jesus wouldn't have needed to come into this world and die to pay for our sins.
"Can God just simply forgive humans?" If God did so, He was neither just nor consistent with his words. The penalty of humans' sins must be paid if humans are to be saved. Note that humans don't need to be saved—God could just leave humans condemned and He is still just. Only because God so loved us that He himself paid for our sins.