Proverbs 3:9 calls us to "Honour the LORD with thy substance, and with the firstfruits of all thine increase." Substance is not only money but the life God has given—our skills, time, labor, and service. When we say "your services are the substance," we mean that the work of our hands and the ministry of our hearts are proper offerings to God. To honor the Lord with our substance is to present the best of what we are and have as worship, recognizing His claim over every part of life.
Practically this means arranging our days and choices so that worship is first. Offer your best work at home, at the office, in church, and in the neighborhood as firstfruits: the first hours of the day, the priority projects, the sacrificial time with others rather than what remains after self. It means submitting our gifts to his service rather than to self-promotion, and doing ordinary tasks as acts of obedience and love to Christ who served us.
Theologically this offering arises from grace, not from a desire to earn God's favor. We give because Christ has given himself for us, and our service is an embodied response to that mercy. When we give our substance—our service—as firstfruits we testify that God is Lord of our labor and that we trust his provision; the biblical firstfruits anticipated God's blessing, and so our giving is both worshipful surrender and hopeful testimony.
So practice offering your services as substance: choose the first, the best, and the surrendered in everyday work and relationships, and let Christ's example shape how you labor. God honors such offerings, shapes your heart, and uses small, faithful acts for his kingdom. Take heart: your faithful service as firstfruits matters to the Lord and is received by him as worship.