Going back to Genesis (15:5-12, 17-18), we continue to hear of the developing covenant the Lord is making with Abram.  Here God promises countless descendants and  a land to call home to an elderly, fatherless nomad.  Improbable as all this seems, God reads Abram’s heart and knows how faith-filled it is.  But, He did not only have to consider his heart to determine this.  Going back to Genesis 12:1, “The LORD said to Abram: Go forth from your land, your relatives, and from your father’s house.”  This to a 75 year old man who unhesitatingly uprooted his family to follow the Lord.  Then he encounters famine and has to move to Egypt and endure the many trials he encountered there.  After Egypt he splits with his nephew Lot who takes the most fruitful land; then he goes to war to rescue Lot when he is captured.  All this while constantly, but unquestioningly, on the move still awaiting the promise of an heir.  This is not to mention the subsequent trials, culminating in the command to sacrifice the son with which he had finally been blessed.  It is no wonder that James says,

Was not Abraham our father justified by works when he offered his son Isaac upon the altar?  You see that faith was active along with his works, and faith was completed by the works.  Thus the scripture was fulfilled that says, “Abraham believed God, and it was credited to him as righteousness,” and he was called “the friend of God.” (Jas 2:21-23)

 It is by faith that we are saved.  But not “faith alone” (sola fide, a pillar of Martin Luther’s theology) which is an unbiblical concept (for starters, see the passage above).  To bring home the point, James goes on to write:

See how a person is justified by works and not by faith alone.(v. 24)

That faith is required for salvation is explained in the Catechism of the Catholic Church:

Believing in Jesus Christ and in the One who sent him for our salvation is necessary for obtaining that salvation. “Since ‘without faith it is impossible to please [God]’ and to attain to the fellowship of his sons, therefore without faith no one has ever attained justification, nor will anyone obtain eternal life ‘But he who endures to the end.'” (161)

Like Abram, we are to walk by faith (see 2 Cor 5:7) and to live by faith, even when it is most difficult — especially when it is most difficult.  To strengthen our faith, it must be exercised.  Let us not “wimp out” on this spiritual workout of utmost importance given to us by the ultimate coach: the Lord God.