"Therefore I thought it necessary to exhort the brethren to go to you ahead of time and prepare your generous gift beforehand, which you had previously promised, that it may be ready as a matter of generosity and not as a grudging obligation." 2 Cor 9:5
The Corinthians had agreed to give an offering for the struggling church at Jerusalem. Paul would be the one to physically collect and deliver the offering. Rather than wait to collect the offering when he got to Corinth, he sent sent some men ahead of him to give the Corinthians plenty of advance notice. This brings up an important point. Giving to the Lord is best done with forethought and prayer. When we take the time to pray and consider what God would have us to give, then giving to the Lord becomes fulfilling, even exciting. In contrast, when we just throw in the plate whatever happens to be in our wallet, giving becomes a "grudging obligation." Something we do out of guilt or necessity rather than love.
Most of us, if we're being honest, would rather receive a gift that was carefully planned and selected in advance by the giver, than something bought at the last minute as an afterthought, just to avoid the doghouse. Does God deserve any less? Take time to prayerfully consider your finances, and what would be a generous/sacrificial amount for you to give to the Lord's work. Then give it cheerfully!