Paul started chapter 9 by saying that, concerning the ministering to the saints, it was superfluous (superfluous means “not needed; unnecessary”) for him to write.  Nevertheless, he did write.  Paul wrote 2 Cor 9 because he wanted the Corinthians to know that:

Their zeal had provoked very many – 2 Cor 9:2 – when Macedonia heard how much Achaia wanted to help the saints, they were stirred up to help them, too.  Generous giving encourages others to give generously, as well.  Forwardness [v.2] means “readiness,” see 2 Cor 8:11.

He had been boasting of their generosity – 2 Cor 9:3-4 – Paul had been boasting to the folks in Macedonia about Achaia’s generosity.  He was concerned that some from Macedonia would travel with him to Corinth and find that they hadn’t given, at all.  Paul said that if they were unprepared, “we (that we say not, ye) should be ashamed.”  If you say you’re going to give, then give.  

Others were coming to make up their bounty – 2 Cor 9:5 – the first time bounty is used in this verse it means “something that is given generously,” in other words, “a generous gift.” The second bounty means “generosity; liberality in giving.”  Paul sent Titus and the two other brethren ahead [2 Cor 8:16-23] to make sure that the Corinthians gave.  He assured them that their gift would be a matter of their liberality in giving; not a matter of his covetousness.

They should give bountifully rather than sparingly – 2 Cor 9:6 – if they were to sow sparingly, they would reap sparingly.  Likewise, through bountiful sowing they would reap bountifully.  They might not have considered that they would reap anything by giving to the poor saints in Jerusalem.  To the contrary, they would reap according to the bountifulness of their giving.  In other words, when you give, you should give as much as you can, not as little as you can.

Each person should give as he purposeth in his heart – 2 Cor 9:7 – purposeth means “to propose as an aim to oneself.”  In other words, each person should make up his own mind how much he’s going to give.  He should not give grudgingly (grudgingly means “unwillingly; reluctantly”) or of necessity (of necessity means by “physical or moral compulsion”). Therefore, they were to give only as much as they were willing to give [2 Cor 8:12] and they were not to be intimidated to give.  The reason is that God loveth a cheerful giver.  You can’t be cheerful if you’re unwilling or being compelled to give.

God will make all grace abound to you – 2 Cor 9:8-11 – we are saved by his grace and we live by his grace.  When you give by his is grace [2 Cor 8:1-3], his grace:

• Gives you all sufficiency in all things – 2 Cor 9:8-10 – therefore, you have everything you need and you can abound in every good work that he wants you to do.  Paul quoted Ps 112:9 to show that God has given you every thing you need.  When you give, he ministers bread for your food and multiplies your seed sown. 
• Increases the fruits of your righteousness – 2 Cor 9:10 – by multiplying your seed sown he increases your fruit.  That is he’ll multiply what you sow and he’ll give you more to sow.
• Enriches you in every thing to all bountifulness – 2 Cor 9:11 – it is the grace of God that makes bountiful sowing bountiful reaping.  And this is not only true in the grace of giving, but it is also true “in every thing.”

Oftentimes, in giving to missions, more emphasis is placed on your faith than God’s grace.  However, we should emphasize the grace of God.  His grace is what makes it work.

By giving to the saints they would:

• Cause abundant thanksgiving to God – 2 Cor 9:11-12 – Paul was thankful to God for their bounty [v.11] and the saints would be thankful to receive their bounty.
• Supply the want of the saints – 2 Cor 9:12 – this was the reason for the gift in the first place.
• Bring glory to God – 2 Cor 9:13 – Experiment means “experience.”  The saints glorify God for Achaia’s subjection to the gospel [you don’t keep the gospel to yourself; you preach it to others and you help others] and their liberal distribution.
• Receive the prayers of the saints – 2 Cor 9:14 – the saints prayed for them.  Their liberality would be a testimony to the exceeding grace of God in them as in Macedonia [2 Cor 8:1-3].

Conclusion: Paul thanked God for his unspeakable gift of grace.  It’s because of his grace that we are even saved and by his grace that we are able to give generously.