Job 1:6

Now there was a day when the sons of God came to present themselves before the Lord, and the Adversary also came among them.
Job 1:6, Modern English Version (MEV)
 
Now we come to some of the weird parts. There are many theories and possible explanations for what the term "sons of God" means, but there is no single meaning for us to stand on. A lot depends on the context. However, one common meaning is that these were might men, men of renown. In this case, however, it doesn't quite seem to fit.
 
Given that Job is thought to be contemporaneous with the patriarchs; Abraham, Isaac or Jacob, and considering they were not only surrounded by people who worshiped pagan gods, that even Abraham's father, at least, had worshiped pagan gods, we can imagine this was meant to represent a gathering of those gods. While we don't always like to think about it, Israel's God was often seen as a God among gods, possibly even the leading God. When we look at this in those terms, it helps things to make a little sense, and we can see the still ridiculous situation the author is setting up for us.
 
For a more detailed insight, we will turn to Albert Barnes’ Notes on the Bible:
 
Now there was a day - Dr. Good renders this, “And the day came.” Tindal.” Now upon a time.” The Chaldee paraphrasist has presumed to specify the time, and renders it, “Now it happened in the day of judgment (or scrutiny, דדינא ביומא), “in the beginning of the year,” that hosts of angels came to stand in judgment before yahweh, and Satan came.” According to this, the judgment occurred once a year, and a solemn investigation was had of the conduct even of the angels. In the Hebrew there is no intimation of the frequency with which this occurred, nor of the time of the year when it happened. The only idea is, that “the sons of God” on a set or appointed day came to stand before God to give an account of what they had done, and to receive further orders in regard to what they were to do. - This is evidently designed to introduce the subsequent events relating to Job. It is language taken from the proceedings of a monarch who had sent forth messengers or ambassadors on important errands through the different provinces of his empire, who now returned to give an account of what they had observed, and of the general state of the kingdom. Such a return would, of course, be made on a fixed day when, in the language of the law, their report would be “returnable,” and when they would be required to give in an account of the state of the kingdom. If it be said that it is inconsistent with the supposition that this book was inspired to suppose such a poetic fiction, I reply,
 
(1) That it is no more so than the parables of the Savior, who often supposes cases, and states them as real occurrences, in order to illustrate some important truth. Yet no one was ever led into error by this.
 
(2) It is in accordance with the language in the Scripture everywhere to describe God as a monarch seated on his throne, surrounded by his ministers, and sending them forth to accomplish important purposes in different parts of his vast empire.
 
It is not absolutely necessary, therefore, to regard this as designed to represent an actual occurrence. It is one of the admissible ornaments of poetry; - as admissible as any other poetic ornament. To represent God as a king is not improper; and if so, it is not improper to represent him with the usual accompaniments of royalty, - surrounded by ministers, and employing angels and messengers for important purposes in his kingdom. This supposition being admitted, all that follows is merely in “keeping,” and is designed to preserve the verisimilitude of the conception. - This idea, however, by no means militates against the supposition that angels are in fact really employed by God in important purposes in the government of his kingdom, nor that Satan has a real existence, and is permitted by God to employ an important agency in the accomplishment of his purposes toward his people. On this verse, however, see the Introduction, Section 1, (4).
 
The sons of God - Angels; compare Job_38:7. The whole narrative supposes that they were celestial beings.
 
Came to present themselves - As having returned from their embassy, and to give an account of what they had observed and done.
 
Before the Lord - Before יהוה yehovâh. On the meaning of this word, see the notes at Isa_1:2. A scene remarkably similar to this is described in 1Ki_22:19-23. Yahweh is there represented as “sitting on his throne, and all the host of heaven standing by him on his right hand and on his left.” He inquires who would go and persuade Ahab that he might go up and fall at Ramoth-gilead? “And there came forth a spirit and stood before the Lord, and said, I will persuade him.” This he promised to do by being “a lying spirit in the mouth of all his prophets.”
 
And Satan came also among them - Margin, “The adversary” came “in the midst of them.” On the general meaning of this passage, and the reasons why Satan is introduced here, and the argument thence derived respecting the age and authorship of the book of Job, see the Introduction, Section 4, (4). The Vulgate renders this by the name “Satan.” The Septuagint: ὁ διάβολος ho diabolos - the devil, or the accuser. The Chaldee, סטנא saṭenā', “Satan.” So the Syriac. Theodotion, ὁ ἀντικείμενος ho antikeimenos - “the adversary.” The word rendered “Satan” שׂטן śâṭân is derived from שׂטן śâṭan “Satan,” to lie in wait, to be an adversary, and hence, it means properly an adversary, an accuser. It is used to denote one who “opposes,” as in war 1Ki_11:14, 1Ki_11:23, 1Ki_11:25; 1Sa_29:4; onc who is an adversary or an accuser in a court of justice Psa_109:6, and one who stands in the way of another; Num_22:22, “And the angel of yahweh stood in the way for an adversary against him” לה לשׂטן leśâṭân lôh, “to oppose him.”
 
It is then used by way of eminence, to denote the “adversary,” and assumes the form of a proper name, and is applied to the great foe of God and man - the malignant spirit who seduces people to evil, and who accuses them before God. Thus, in Zec_3:1-2, “And he showed me Joshua the priest standing before the angel of the Lord, and Satan standing at his right hand to resist him. And the Loan said unto Satan, The Lord rebuke thee, O Satan;” compare Rev_12:10, “Now is come salvation - for the accuser ὁ κατηγορῶν ho katēgorōn - that is, Satan, see Rev_12:9) of our brethren is cast down, which accused them before our God day and night.” - The word does not often occur in the Old Testament. It is found in the various forms of a verb and a noun in only the following places. As a verb, in the sense of being an adversary, Psa_71:13; Psa_109:4, Psa_109:20, Psa_109:29; Zec_3:1; Psa_38:20; as a noun, rendered “adversary” and “adversaries,” 1Ki_5:4; 1Ki_11:14, 1Ki_11:23, 1Ki_11:25; Num_22:22, Num_22:32; 1Sa_29:4; 2Sa_19:22; rendered “Satan,” 1Ch_21:1; Psa_109:6; Job_1:6-9, Job_1:12; Job_2:1-4, Job_2:6-7; Zec_3:2; and once rendered “an accusation,” Ezr_4:6.
 
It was a word, therefore, early used in the sense of an adversary or accuser, and was applied to anyone who sustained this character, until it finally came to be used as a proper name, to denote, by way of eminence, the prince of evil spirits, as the adversary or accuser of people. An opinion has been adopted in modern times by Herder, Eichhorn, Dathe, Ilgen, and some others, that the being here referred to by the name of Satan is not the malignant spirit, the enemy of God, the Devil, but is one of the sons of God, “a faithful, but too suspicious servant of yahweh.” According to this, God is represented as holding a council to determine the state of his dominions. In this council, Satan, a zealous servant of yahweh, to whom had been assigned the honorable office of visiting different parts of the earth, for the purpose of observing the conduct of the subjects of yahweh, makes his appearance on his return with others.
Such was the piety of Job, that it had attracted the special attention of yahweh, and he puts the question to Satan, whether in his journey be had remarked this illustrious example of virtue. Satan, who, from what he has observed on earth, is supposed to have lost all confidence in the reality and genuineness of the virtue which man may exhibit, suggests that he doubts whether even Job serves God from a disinterested motive; that God had encompassed him with blessings, and that his virtue is the mere result of circumstances; and that if his comforts were removed he would be found as destitute of principle as any other man. Satan, according to this, is a suspicious minister of yahweh, not a malignant spirit; he inflicts on Job only what he is ordered to by God, and nothing because he is himself malignant. Of this opinion Gesenius remarks (Lexicon), that it “is now universally exploded.”
 
An insuperable objection to this view is, that it does not accord with the character usually ascribed to Satan in the Bible, and especially that the disposition attributed to him in the narrative before us is wholly inconsistent with this view. He is a malignant being; an accuser; one delighting in the opportunity of charging a holy man with hypocrisy, and in the permission to inflict tortures on him, and who goes as far in producing misery as he is allowed - restrained from destroying him only by the express command of God. - In Arabic the word Satan is often applied to a serpent. Thus, Gjauhari, as quoted by Schultens, says, “The Arabs call a serpent Satan, especially one that is conspicuous by its crest, head, and odious appearance.” It is applied also to any object or being that is evil. Thus, the Scholiast on Hariri, as quoted by Schultens also, says, “Everything that is obstinately rebellious, opposed, and removed from good, of genii, human beings, and beasts, is called Satan.” - The general notion of an adversary and an opponent is found everywhere in the meaning of the word. - Dr. Good remarks on this verse, “We have here another proof that, in the system of patriarchal theology, the evil spirits, as well as the good, were equally amenable to the Almighty, and were equally cited, at definite periods, to answer for their conduct at his bar.”
 
Rosenmuller remarks well on this verse, “It is to be observed, that Satan, no less than the other celestial spirits, is subject to the government of God, and dependent on his commands (compare Job_2:1) where Satan equally with the sons of God (אלהים בן bên 'ĕlohı̂ym) is said to present himself before God (לחהיצב lehı̂tyatsēb; that is, λειτουργεῖν leitourgein), to minister. Yahweh uses the ministry of this demon (hujus daemonis) to execute punishment, or when from any other cause it seemed good to him to send evil upon men. But he, although incensed against the race of mortals, and desirous of injuring, is yet described as bound with a chain, and never dares to touch the pious unless God relaxes the reins. Satan, in walking round the earth, could certainly attentively consider Job, but to injure him he could not, unless permission had been given him.”