Give

They even did more than we had hoped, for their first action was to give themselves to the Lord and to us, just as God wanted them to do. (2 Cor 8:5)

Paul talks about how the Macedonian Christians gave themselves to the Lord first, then to His ministry and partnership. When you give to First Church, you are giving to the Lord through giving to First Church. 

Since you excel in so many ways—in your faith, your gifted speakers, your knowledge, your enthusiasm, and your love from us—I want you to excel also in this gracious act of giving. (2 Cor 8:7)

Just as we work to develop our faith, our love, and other aspects of our Christian life, so also should we work to grow in our practice of generosity. 

Now you should finish what you started. Let the eagerness you showed in the beginning be matched now by your giving. Give in proportion to what you have. (2 Cor 8:11)

When we give a percentage of what we earn back to the Lord in worship, it helps us prepare to give, cheerfully give, and consistently give in worship to the Lord. Many recommend that a good percentage to aim for is a tenth (10%). Yet, some should consider more than 10%, and for others, 10% is out of the question to start with! That's ok! Figure a percent, give it cheerfully and consistently, and work towards developing in the grace of giving by increasing your percentage. 

Whatever you give is acceptable if you give it eagerly. And give according to what you have, not what you don’t have. (2 Cor 8:12)
… I want it to be a willing gift, not one given grudgingly. (2 Cor 9:5)
You must each decide in your heart how much to give. And don’t give reluctantly or in response to pressure. “For God loves a person who gives cheerfully.” (2 Cor 9:7)

When we say giving is worship to God, we mean it. We are not pressuring you to give, nor will we ever intend to do so. We may inspire and encourage you to grow in the grace of giving, but we will do our best to avoid anything of "pressuring." That said, once you have determined your percentage and decided to give in worship, God will be honored as your giving to Him is truly a dedicated act of worship from your heart. 

Now regarding your question about the money being collected for God’s people in Jerusalem. You should follow the same procedure I gave to the churches in Galatia. On the first day of each week, you should each put aside a portion of the money you have earned. Don’t wait until I get there and then try to collect it all at once. (1 Cor 16:1-2)

In Paul's time, debit cards did not exist; not even paper dollar bills! Gold, coins, and other tokens of currency made up his world. In that reality, Paul says, the first thing to do is set aside a portion (or percentage) of the money that has been earned. And the crazy thing, Paul did not just tell this to one church in Corinth, but to many churches throughout Galatia.

Week in and week out, as the Christians in Corinth and Galatia earned money, they set it apart (consecrated it) to the Lord in worship, following Paul's instructions. However and whenever you earn income (weekly, bi-weekly, monthly, etc.), it is a best practice to consistently give a percentage back in worship to God first.