I grew up being taught the most common evangelical definition of grace...underserved favor. The prevailing proof text for this definition is by the Apostle Paul in Ephesians 2:8, 9: "For it is by grace you have been saved, through faith - and this not from yourselves, it is the gift of God - not by works, so that no one can boast."
Now it is absolutely true that grace means kindness and that God's kindness is not something we earn; it is who he is. But just as James says "faith without works is dead" (2:26b), Paul goes on to say that "we are God's workmanship, created in Christ Jesus to do good works" (Ephesians 2:10). So while volumes upon volumes have been written about the mystery of grace, our tendency is to swing to one side of the pendulum or the other when it comes to trying to wrap our mind around grace, faith, and works. Where does the work of God meet the work of man?
But there is another definition of grace that doesn't seem to be emphasized enough even though there are many more scriptures that support it than the definition of kindness/favor...and that is strength...the strength and power of God that enables us do what he tells us. The vast majority of scriptures about grace are in the context of strength.
Hebrews 13:9b: "It is good for our hearts to be strengthened by grace." 1 Corinthians 15:10: "But by the grace of God I am what I am, and his grace to me was not without effect. No, I worked harder than all of them - yet not I, but the grace of God that was with me." 1 Peter 4:10, 11b: "Each of you should use whatever gift you have received to serve others, as faithful stewards of God's grace in its various forms. If anyone serves, they should do so with the strength God provides." 2 Timothy 2:1: "You then, my son, be strong in the grace that is in Christ Jesus." Hebrews 4:16: "Let us then approach God's throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need."
Another word to summarize this second definition of grace is ability. God's grace is the ability to enter into relationship with him and then to grow that relationship which translates into help in relationship with others.
So now I describe the phrase "by grace through faith" like this...the ability to activate (grace) our capacity to trust and depend on God (faith). (See my blog titled "The Language of Worship Part 3: How We Talk About Faith.") What I love about this description is that it maintains the sense of God as the source but also paints the picture of relationship. And relationship takes more than one person. God's part meets our part and our part meets God's part. God always looks through the lens of relationship. Worship equals relationship. Relationship is the purpose of life. Worship is Life!