'Free will' in the Bible

With a free will-offering I sacrifice to Thee, I thank Thy name, O Jehovah, for it is good,

A shower of free-will gifts thou shakest out, O God. Thine inheritance, when it hath been weary, Thou hast established it.

Thy people are free-will gifts in the day of Thy strength, in the honours of holiness, From the womb, from the morning, Thou hast the dew of thy youth.

Free-will-offerings of my mouth, Accept, I pray Thee, O Jehovah, And Thy judgments teach Thou me.