Like good stewards of the manifold grace of God, serve one another with whatever gift each of you has received. Whoever speaks must do so as one speaking the very words of God; whoever serves must do so with the strength that God supplies, so that God may be glorified in all things through Jesus Christ.
I Peter 4:10-11 (NRSV)
When we accept Christ as our Savior, everything we do should reflect the master we serve. What is important and unimportant in our lives changes because we are grateful that he gave his life for us and want to form our characters to be more like Him.
Our professions or hobbies provide a means to witness. Our time management reflects self-centeredness or Christ-centeredness. Where our money goes sets our priorities in life.
We are stewards of God's grace, because it is through grace that He saved us from an eternity separated from love. And it is here on earth, whether it is Christ's birthday or not, as God's children we are to show others the love He has shown us.