'Voluntarily' in the Bible

Be sure you do whatever you promise, because you have given your word voluntarily to the LORD your God.

If their fathers or brothers come complaining to us, we'll tell them "Be generous! Give them to us voluntarily, because we didn't take anyone to be a wife for the men of the tribe of Benjamin as a result of the battle. And you haven't incurred guilt by giving your daughters to them.'"

Then the people rejoiced because they had given voluntarily, since with a devoted heart they had freely given to the LORD.

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.

For if I preach voluntarily, I get a reward, but if I am unwilling to do it, I am still entrusted with that obligation.