'Voluntary' in the Bible
"If his sacrifice accompanies a fulfilled vow or is a voluntary offering, it is to be eaten on the day the offeror brings the sacrifice. Anything left over is to be eaten the next day,
when you enter the land where you'll be living that I'm about to give you, you are to make an offering by fire to the LORD, either a burnt offering, a sacrificial offering to fulfill a vow, or a voluntary offering at the appointed time, to make a pleasing aroma to the LORD either from your cattle or from your flocks.
"You won't be allowed to eat your tithe of grain, new wine, oil, the firstborn of your herd and flock, your voluntary offerings that you pledged, your free-will offerings, and the works of your hands in your own cities.
Jehoash spoke to the priests about all of the proceeds of the consecrated gifts that were being brought into the LORD's Temple, cash from every man who was traveling through the area, cash obtained by personal assessment, and all the cash that came through voluntary gifts into the LORD's Temple:
So the leaders of the ancestral households presented their voluntary offerings, as did the leaders of the tribes, the commanders of thousands and hundreds, and the officials in charge of the king's business.
But who am I, and who are my people, that we make such voluntary offerings as these? For all things come from you, and from your own hand we are giving to you.
Imnah the descendant of Levi's son Kore, keeper of the eastern gate, was in charge of voluntary offerings to God, apportioning contributions for the LORD and the most holy things.
His officers contributed a voluntary offering to the people, the priests, and the descendants of Levi. Hilkiah, Zechariah, and Jehiel, the officials who supervised God's Temple, gave 2,600 animals from their flocks to the priests for Passover offerings, along with 300 bulls.
Furthermore, everyone who wishes to repatriate from any territory where he now resides is to receive assistance from his fellow residents in the form of silver, gold, equipment, and pack animals, in addition to voluntary offerings for the Temple of the God of Jerusalem.
So all of their neighbors equipped the travelers with silver, gold, equipment, pack animals, and valuable goods, in addition to voluntary offerings.
After that, they offered all of the continual burnt offerings and the New Moon sacrifices for all of the designated festivals of the LORD that were being consecrated, along with all the voluntary offerings that were dedicated to the LORD.
LORD, please accept my voluntary offerings of praise, and teach me your judgments.
Whenever the Regent Prince presents a voluntary offering, burnt offering, or peace offering, he is to present it voluntarily to the LORD, and the east-facing gate is to be opened for him. He is to provide his burnt offering and peace offering as he does on the Sabbath. When he leaves, the gate is to be shut behind him.