"For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life." -John 3:16
Christianity is founded on generosity. It begins with a God sending His own son to lay down his life for other's sins. If we look at sin like a debt, a debt that collects before God, then our sin has put us into a bankrupt state before God. The generous God, seeing we have incurred a debt we cannot pay off allows his son to take the debt of all our sin and cancel it through his sacrifice made on the cross.
"For while we were still weak, at the right time Christ died for the ungodly. Indeed, rarely will anyone die for a righteous person - though perhaps for a good person someone might actually dare to die. But God proves his love for us in that while we were sinners Christ died for us. Much more surely then, now that we have been justified by his blood, will we be saved through him from the wrath of God. For if while were enemies, we were reconciled to God through the death of his Son, much more surely, having been reconciled, will we be saved by his life. But more than that, we even boast in God through our Lord Jesus Christ, through whole we have no received reconciliation" (Romans 5:6-11).
Generosity begins with God and Jesus Christ is the gift that we receive. And who receives a gift and doesn't respond. What type of response should we have? Generosity is the fruit we bear having received life through Christ. Like Christ we don't discriminate who should receive our generosity but rather we pour it out on everyone we can, godly and ungodly, friend and foe. With every generous act we are made more in the likeness of Christ as we lose who we are and gain new identity in Christ. Scripture reminds us in myriad places to respond in this way,
"One gives freely, yet grows all the richer;
another withholds what he should give, and only suffers want.
Whoever brings blessing will be enriched,
and one who waters will himself be watered." -Proverbs 11: 24-25
"Jesus looked up and saw the rich putting their gifts into the offering box, and he saw a poor widow put in two small copper coins. And he said, “Truly, I tell you, this poor widow has put in more than all of them. For they all contributed out of their abundance, but she out of her poverty put in all she had to live on.” -Luke 21:1-4
"And now I commit you to God and to the message of His grace, which is able to build you up and to give you an inheritance among all who are sanctified. I have not coveted anyone’s silver or gold or clothing. You yourselves know that these hands have provided for my needs and for those who were with me. In every way I’ve shown you that by laboring like this, it is necessary to help the weak and to keep in mind the words of the Lord Jesus, for He said, “It is more blessed to give than to receive.” Acts 20: 32-35
For if the readiness is there, it is acceptable according to what a person has, not according to what he does not have. For I do not mean that others should be eased and you burdened, but that as a matter of fairness your abundance at the present time should supply their need, so that their abundance may supply your need, that there may be fairness. As it is written, 'Whoever gathered much had nothing left over, and whoever gathered little had no lack.'” - 2 Corinthians 8: 12-15
And we should not feel forced to be generous. For me, I think it is a response to the depth one has in Christ. For the deeper one realizes the debt Christ paid for them, the more they will feel called to respond to that for Scripture tells us,
"The point is this: whoever sows sparingly will also reap sparingly, and whoever sows bountifully will also reap bountifully. Each one must give as he has decided in his heart, not reluctantly or under compulsion, for God loves a cheerful giver. And God is able to make all grace abound to you, so that having all sufficiency in all things at all times, you may abound in every good work." -2 Corinthians 9:6-8
When we live out what Christ lived out before the world, the church will collectively demonstrate the love Christ has for the world through us. If we can live this out in our church then we can encourage those around us to do the same.
"By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers. But if anyone has the world’s goods and sees his brother in need, yet closes his heart against him, how does God’s love abide in him? Little children, let us not love in word or talk but in deed and in truth." 1 John 3:16-18
For me, this is the one of the highest callings a Christian should try and live out. It is lived out by reflecting on Christ alone, meditating on his love and generosity towards humanity. Daily in our prayers we can do this and let a generous heart be our response in the world.