to set the will on a course of action: to be willing, to consent, or to take something upon oneself
TranslatabilityPartialCertaintyStrong
This verb marks the moment a person's will settles on doing something. Depending on the situation it can mean simply agreeing to what someone asks, graciously choosing to grant a favor, or boldly taking the initiative to act. The common thread is a decision to go ahead, not a feeling.
That single core fans out into three everyday uses. A person may accede to persuasion or a circumstance, as when Moses was content to stay with Jethro or Naaman pressed Gehazi to accept his gifts. The word also serves as a courteous request that a greater person "be pleased to" act, especially in prayer, as when David asks God to bless his house. And it can describe someone venturing to take a step, as when Abraham dares to speak to the Lord or David tries to walk in Saul's armor. A close relative in feel is אָבָה, the plain verb for consenting or being willing.
The same willingness can read as stubborn insistence when the subject is an opponent: the Canaanites "were determined" to keep living in the land. English translations reach for very different words here, which can hide that one Hebrew verb is at work.
Nuances
1ato be willing, consent, or be content to do something; for an opponent, to be determined or bent on it
carries the note of daring to take initiative before someone greaterGen 18:27
Both
both describe taking it upon oneself to make a moveGen 18:31
Only venture
the English word can imply risk or gamble, while the Hebrew stresses the humble boldness of speaking up at all
“undertake”
Comparison data is not available for this English gloss yet.
How ya'al differs from similar Hebrew words
אָבָהthe plain verb for consenting or being willing, almost always in the negative ("would not"); it lacks this word's extra shades of graciously granting a favor or venturing to take initiative.
Names a person resolving to do something themselves, taking it upon themselves to act, often softened to a courteous please be so good as to.Gen 18:272Sa 7:29
Shades into being content or settling down to do a thing, agreeing to stay or go ahead with it rather than answering a yes-or-no demand.Exo 2:21Jdg 19:6Jos 7:7
Both
Both translate as be willing and both turn on a person's readiness to do or allow a thing, so English Bibles render either one with willing or content.Isa 1:191Sa 17:39
Names assent to what someone else asks or proposes, so it almost always shows up as a refusal: the person who will not give in, will not go along, will not say yes.Deu 1:261Sa 15:9Pro 1:10
Used even of an animal that will not submit to a master's wishes, showing the focus is on bending one's will to another's demand rather than on choosing to act.Job 39:9
חָפֵץcenters on delighting in or desiring something, an inclination of pleasure, whereas this word names the decision to act rather than the pleasure behind it.
חָלַלmeans to begin an action in the plain sense of starting it in time; this word overlaps only in the "undertake" sense, where it adds the note of willingly setting oneself to the task.
ya'al in the other biblical languages
θέλωGreek“to will/desire”the common Greek verb for willing or wishing; it is the broadest match for this word's core of the will choosing to act.
εὐδοκέωGreek“to delight”means to be pleased or take pleasure in, matching the sense where God or a superior is graciously pleased to do something.
τολμάωGreek“be bold”means to dare or venture, matching the sense where someone presumes to take a bold step, as Abraham venturing to speak to God.
What scholars say about ya'al
The standard lexica treat the hiphil of יאל II as a volitional verb clustering around three uses: to undertake, make a start, or venture (Gen 18:27, 31; Deut 1:5;1 Sam 17:39); to be willing, consent, or be content (Exod 2:21;Judg 1:27, 35; 17:11; 19:6; Josh 17:12;2 Kgs 5:23; 6:3; Hos 5:11); and to be pleased or graciously want to do something, often of God or in polite entreaty (1 Sam 12:22;2 Sam 7:29;1 Chr 17:27;Job 6:9, 28). BDB and HALOT keep these as shades of one root, distinct from the homonymous יאל I "to be foolish." The boundary between the "be willing/content" and "be pleased" uses is partly a matter of register, since the polite request form הואל נא spans both.