Moses’ people gave far more than was needed for the tabernacle, moved not by obligation but by a willing heart, and the gold, silver, and bronze inventoried in Exodus 38 becomes a picture of abundance freely offered to God.
That Old Testament generosity points forward to a greater gift: Paul writes that though Christ was rich, he became poor for our sake, so that we through his poverty might become immeasurably rich. The lavish gift of the tabernacle is a shadow; the lavish gift of God in Christ is the substance, and it is meant to move his people to give as willingly as Israel once did.