Behold, this is the joy of his way - This is evidently sarcastic. "Lo! such is the joy of his course! He boasts of joy, as all hypocrites do, but his joy endures only for a little time. This is the end of it. He is cut down and removed, and the earth and the heavens disown him!"
And out of the earth shall others grow - This image is still derived from the tree or plant. The meaning is, that such a plant would be taken away, and that others would spring up in its place which the earth would not be ashamed of. So the hypocrite is removed to make way for others who will be sincere, and who will be useful. Hypocrites and useless people in the church are removed to make way for others who will be active and devoted to the cause of the Redeemer. A similar sentiment occurs in Job 27:16-17. This closes, as I suppose, the quotation which Bildad makes from the poets of the former age, and in the remainder of the chapter he states another truth pertaining to the righteous. This fragment is one of the most interesting that can be found any where. As a relic of the earliest times it is exceedingly valuable; as an illustration of the argument in hand; and of the course of events in this world, it is eminently beautiful. It is as true now as it was when uttered before the flood, and may be used now as describing the doom of the hypocrite, with as much propriety as then, and it may be regarded as one of the way-marks in human affairs, showing that the government of God, and the manner of his dispensations, are always substantially the same.

Behold this is the joy of his way - A strong irony. Here is the issue of all his mirth, of his sports, games, and pastimes! See the unfeeling, domineering, polluting and polluted scape-grace, levelled with those whom he had despised, a servant of servants, or unable to work through his debaucheries, cringing for a morsel of bread, or ingloriously ending his days in that bane of any well-ordered and civilized state, a parish workhouse. This also I have most literally witnessed.
Out of the earth shall others gross - As in the preceding case, when one plant or tree is blasted or cut down, another may be planted in the same place; so, when a spendthrift has run through his property, another possesses his inheritance, and grows up from that soil in which he himself might have continued to flourish, had it not been for his extravagance and folly. This verse Mr. Good applies to God himself, with no advantage to the argument, nor elucidation of the sense, that I can see. I shall give his translation, and refer to his learned notes for his vindication of the version he has given: -
"Behold the Eternal (הוא) exulting in his course;
Even over his dust shall raise up another."
In this way none of the ancient versions have understood the passage. I believe it to be a strong irony, similar to that which some think flowed from the pen of the same writer: Rejoice, O young man, in thy youth; and let thy heart cheer thee in the days of thy youth; and walk in the ways of thine heart, and in the sight of thine eyes. But know thou, that for all these God will bring thee into judgment; Ecclesiastes 11:9. These two places illustrate each other.

Behold, this [is] the joy (l) of his way, and out of the earth shall others grow.
(l) To be planted in another place, where it may grow as it pleases.

Behold, this is the joy of his way,.... Of the state and condition of the hypocrite, who, while he is in outward prosperity, exults and rejoices, but his joy is but short, it is but for a moment, Job 20:5; and this is what it comes to at last, and issues in, even entire destruction from his place; which, because it may seem strange and wonderful, and is worthy of notice and consideration, as well as to express a certainty of it, the word "behold" is prefixed; though this also is understood, by some, of good men who have much spiritual joy in their present state and condition, be it what it will; they have joy and peace in believing, even joy unspeakable, and full of glory; they have joy in the Lord, and in his ways in which they walk, when they have trouble in the world; they rejoice and even glory in tribulation, and are cheerful be they where they will, though removed from their native place and country; and especially this will be their case when they are transplanted from earth to heaven, the better and heavenly country:
and out of the earth shall others grow; in their room and stead; where the tall flourishing tree once stood, but now utterly destroyed, other trees should grow; signifying, either the children of the hypocrites and wicked men, that should spring up in their place and imitate them, and come to the same end; or rather such as were strangers to them, that should inherit their substance and estates; and it may be good men that should succeed them, and come into the possession of all their wealth, even such as were before in mean circumstances, and so may be said to come "out of the earth": it may be rendered, "out of another dust" or "earth shall they grow" (q); signifying, that the wicked should be utterly destroyed, they and theirs; and that such as were of another family, and as it were of another earth and country, should stand in their place; see Job 27:16; this may be interpreted of good men, who, though they die, others are raised up in their stead; God will have a seed to serve him as long as the sun and moon endure; though they are forced to fly from their native place, being persecuted, to strange cities, or removed into the heavenly regions, yet God raises up others to till up their places, and oftentimes out of other families, even of the ungodly, to support his cause and interest; and understanding the whole of truly righteous persons seems best to connect the sense with the following words.
(q) "de pulvere alio", Montanus, Bolducius, Cocceius; so the Targum; "de terra alia", Pagninus, Mercerus.

Bitter irony. The hypocrite boasts of joy. This then is his "joy" at the last.
and out of the earth--others immediately, who take the place of the man thus punished; not godly men (Matthew 3:9). For the place of the weeds is among stones, where the gardener wishes no plants. But, ungodly; a fresh crop of weeds always springs up in the place of those torn up: there is no end of hypocrites on earth [UMBREIT].

Behold - This is the issue of the flourishing state. This all his joy comes to. And, &c. - Out of the same earth or place shall another tree grow.