What is faith?

What is faith? Is it something we must work for? Is it something that is given freely?

According to the passage below Abraham's faith is what set him apart from those who didn't believe. Faith is something that we all have been given, the only works on our end is to believe, as Abraham believed, and it was accounted to him for righteousness.

Romans 4:1-8
1What then shall we say that Abraham our father has found according to the flesh?  2 For if Abraham was justified by works, he has something to boast about, but not before God.  3 For what does the Scripture say? “Abraham believed God, and it was accounted to him for righteousness.”  4 Now to him who works, the wages are not counted as grace but as debt.
5 But to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness,  6 just as David also describes the blessedness of the man to whom God imputes righteousness apart from works:
7 “Blessed are those whose lawless deeds are forgiven,
And whose sins are covered;
8 Blessed is the man to whom the Lord shall not impute sin.”