Whenever you give God your firstfruits, you not only give Him the first, you give Him the best. In Malachi 1 the Israelites brought God the worst of their leftovers for their sacrifices–the sick, blind, and lame animals. Sometimes that is what we bring God–our leftover time, energy, and devotion. We come to God when we’re not at our peak.
The story of Cain and Abel serves as a reminder that God is not pleased with those who do not offer firstfruits. “Abel, on his part also brought the firstlings of his flock and of their fat portions. And the Lord had regard for Abel and for his offering; but for Cain and for his offering He had no regard” (Genesis 4:4-5). Cain wound up killing his brother over this incident. Abel brought God the best because he believed God desired and deserved the best. By his offering, Cain showed that he thought God only deserved something, not the best.
If we’re not worshiping God by bringing Him our firstfruits, we are likely giving our firstfruits to something else. What gets your best time and your undivided attention? You give those to whatever is your priority.
Regarding money, “firstfruits” refers to the tithe, or the tenth. You must bring the whole tithe before you bring an offering. Deuteronomy 14:23 says we are to give the tithe “that [we] may learn to fear the Lord.” Whenever we give the tenth first, we’re honoring God as God.
God wants the prime of your life; He doesn’t want the leftovers.