Instances of συνερχομαι having a euphemistic meaning of "to unite in an intimate relationship" (cf. Matthew 1:18)

In Matt 1:18, we read:

 

Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together (συνερχομαι), she was found with child of the Holy Ghost.

 

While the general meaning of συνερχομαι is simply “to come together” (as in to meet/assemble), it does have a sexual connotation. In BDAG, we read the following (note how it references Matt 1:18 in support for this meaning):

 

3. to unite in an intimate relationship, come together in a sexual context (X., Mem. 2, 2, 4; Diod. S. 3, 58, 4; Ps.-Apollod. 1, 3, 3; Philo, Virt. 40; 111; Jos., Ant. 7, 168; 213) ἐπὶ τὸ αὐτό σ. 1 Cor 7:5 v.l. In πρὶν ἢ συνελθεῖν αὐτούς Mt 1:18 domestic and marital relations are combined. (In marriage contracts in pap πρὸς γάμον τινὶ συνελθεῖν means ‘marry’. Also without πρὸς γάμον: BGU 970, 13 [II AD] συνηρχόμην τῷ προγεγραμμένῳ μου ἀνδρί).—M-M. TW.

 

Here are the sources referenced by BDAG:

 

Xenophon, Memorabilia 2.2.4:

 

καὶ μὴν ουʼ τῶν γε ἀφροδισίων ἕνεκα παιδοποιεῖσθαι τοὺς ἀνθρώπους ὑπολαμβάνεις, ἐπεὶ τούτου γε τῶν ἀπολυσόντων μεσταὶ μὲν αἱ ὁδοί, μεστὰ δὲ τὰ οἰκήματα. φανεροὶ δʼ ἐσμὲν καὶ σκοπούμενοι ἐξ ὁποίων ἂν γυναικῶν βέλτιστα ἡμῖν τέκνα γένοιτο· αἷς συνελθόντες τεκνοποιούμεθα

Of course you don’t suppose that lust provokes men to beget children, when the streets and the stews are full of means to satisfy that? We obviously select for wives the women who will bear us the best children, and then marry them to raise a family.

 

Diod. 3.58.4:

 

τὴν οὖν Κυβέλην εἰς ἀκμὴν ἡλικίας ἐλθοῦσαν ἀγαπῆσαι τῶν ἐγχωρίων τινὰ νεανίσκον τὸν προσαγορευόμενον μὲν Ἄττιν, ὕστερον δ᾽ ἐπικληθέντα Πάπαν: συνελθοῦσαν δ᾽ εἰς ὁμιλίαν αὐτῷ λάθρᾳ καὶ γενομένην ἔγκυον ἐπιγνωσθῆναι κατὰ τοῦτον τὸν καιρὸν ὑπὸ τῶν γονέων.

At that time Cybele, in the prime of life, came to be loved by the villagers a young man called Attin, later called Pope: they gathered to speak to him secretly and became pregnant at that time it was known by the parents.

 

Ps.-Apollod. 1, 3, 3

 

Ευρε δε 'Ορφευς και τα Διονυσου μυστηρια, και τεθαπται περι την Πιεριαν διασπασθείς υπο των μαιναδων. Κλειω δε Πειρου του Μάγνητος ηρασθη κατά ημνιν 'Αφροδίτης (ωνειδισε γαρ αυτή τον του 'Αδωνιδος ερωτα), συνελθουσα δε εγεννησεν εξ αυτου παιδα 'Υαχινθον, ου Θαμυρις ο Φιλαμμωνος και 'Αργιοπης νυμφης ισχει ερωτα, προωτοσ αρξαμενος εραν αρρενων.

Orpheus and the Mysteries of Dionysus were found, and they were scattered around Pieria under the Maenads. Clio and Pyrrhus of Magnetus fell in love with Aphrodite (for she made Adonis love her), and when she came together, she gave birth to a child from him, Hyachinth, and Thamyris, Philammonus, and Argiope, the nymph, were in love, the first of which was male.

 

Philo, De virtutibus 1:40:

 

καὶ πλησίον γενόμεναι βλέμμασιν ἑταιρικοῖς καὶ στωμυλίᾳ λόγων καὶ σχέσεσι καὶ κινήσεσιν ἀκολάστοις δελεάζουσι τῆς νεότητος τὴν ὀλιγόφρονα μοῖραν, ἀνερμάτιστα καὶ ἀνίδρυτα ἤθη· καὶ διὰ τῆς τῶν σωμάτων αἰσχύνης ἀγκιστρευσάμεναι τὰς ψυχὰς τῶν συνελθόντων, ἐπὶ θυσίας ἀθύτους καὶ σπονδὰς ἀσυμβάτους καλέσασαι τῶν χειροκμήτων, ἀλλοτριοῦσι τῆς τοῦ ἑνὸς καὶ ὄντως ὄντος θεραπείας θεοῦ.

And when they came near to them they put forth immodest wanton looks, and sought to entice them with caressing words, and dances, and lascivious movements; and in this way they enticed the shallow-minded company of the young men, youths whose dispositions had no ballast nor steadiness in them. And by the shame of their own bodies they captivated the souls of those who came to them, bringing them over to unholy sacrifices which ought not to have been sacrificed, and to libations which should never have been offered in honor of deities made with hands, and thus they alienated them from the worship of the one only and truly divine God. And when they had accomplished their purpose, they sent the glad tidings to the men of their nation;

 

Philo, De virtutibus 1:111:

 

ἐπικουφιεῖς δὲ τὰς μὲν τῆς κεφαλῆς τρίχας ἀποκείρας, περιελὼν δὲ ὄνυχας, ἀπαμφιάσας δὲ τὴν ἐσθῆτα ἣν ἔχουσα ἐζωγρήθη, τριάκοντα δὲ ἡμέρας ἀνεὶς καὶ ἐπιτρέψας αὐτῇ πενθῆσαι καὶ ἀποδακρῦσαι μετὰ ἀδείας πατέρα καὶ μητέρα καὶ τοὺς ἄλλους οἰκείους, ὧν ἀπεζεύχθη τεθνεώτων ἢ θανάτου χείρους ὑπομενόντων τὰς ἐν δουλείᾳ συμφοράς· μετὰ δὲ ταῦτα ὡς γαμετῇ νόμῳ συνέρχου.

and you will alleviate her sufferings if you cut the hair of her head, and trim her nails, and take off from her the garment which she wore when she was taken prisoner, and leave her alone for thirty days, during which period you shall permit her with impunity to mourn and bewail her father and her mother, and her other relations, from whom she has been separated by their death, or by their being subjected to the calamity of slavery which is worse than death.

 

Josephus, Antiquities of the Jews 7:168:

 

ὡς δὲ τὸ κελευσθὲν ἐγένετο τὴν ἀδελφὴν ἠξίωσεν εἰς τὸν ἐνδοτέρω τὸ δεῖπνον οἶκον αὐτῷ παρενεγκεῖν ποιησάσης δὲ τοῦτο τῆς κόρης λαβόμενος αὐτῆς συνελθεῖν αὐτῷ πείθειν ἐπειρᾶτο ἀνακραγοῦσα δ᾽ ἡ παῖς ἀλλὰ μὴ σύ γε τοῦτο βιάσῃ με μηδὲ ἀσεβήσῃς εἶπεν ἀδελφέ τοὺς νόμους παραβὰς καὶ δεινῇ περιβαλὼν σαυτὸν αἰσχύνῃ παῦσαι δ᾽ οὕτως ἀδίκου καὶ μιαρᾶς ἐπιθυμίας ἐξ ἧς ὀνείδη καὶ κακοδοξίαν

As soon as what he had commanded was done, he desired his sister to bring his supper to him into the inner parlour; which, when the damsel had done, he took hold of her, and endeavoured to persuade her to lie with him. Whereupon the damsel cried out, and said, ``Nay, brother, do not force me, nor be so wicked as to transgress the laws, and bring upon yourself the utmost confusion. Curb your unrighteous and impure lust, from which our house will get nothing but reproach and disgrace.''

 

Josephus, Antiquities of the Jews 7:213:

 

μεμένηκε δ᾽ ἐπὶ τῆς αὐτῆς υἱοῦ παραλαβόντος ταῦτα λέγων ἔπειθεν ὕποπτον γὰρ αὐτὸν εἶχε καὶ καλέσας τὸν Ἀχιτόφελον συνεβουλεύετο αὐτῷ τί δεῖ ποιεῖν ὁ δὲ παρῄνεσε ταῖς τοῦ πατρὸς αὐτὸν παλλακαῖς συνελθεῖν ἐκ τούτου γὰρ εἴσεσθαι τὸν λαὸν ἔλεγε πιστεύσαντα ὡς ἀδιάλλακτά σοι τὰ πρὸς αὐτόν ἐστι καὶ μετὰ πολλῆς συστρατεύσεσθαι προθυμίας ἐπὶ τὸν πατέρα μέχρι δεῦρο γὰρ φανερὰν ἔχθραν ἀναλαμβάνειν δεδιέναι προσδοκῶντας ὑμᾶς ὁμονοήσειν

This speech persuaded Absalom, who before suspected Hushai. And now he called Ahithophel, and consulted with him what he ought to do: he persuaded him to go in to his father's concubines; for he said, that ``by this action the people would believe that your difference with your father is irreconcilable, and will hence fight with great alacrity against your father, for hereto they are afraid of taking up open enmity against him, out of an expectation that you will be reconciled again.''

 

1 Cor 7:5 in P46 (early/middle 2^nd century):

 

μη αποστερείτε αλληλους ει μητι εκ συμφωνου προς καιρον ινα σχολασητε τη προσευχη και παλιν επι το αυτό συχερχεσθε ινα μη πειραζη υμασ ο σατανος δια την ακρα σιαν υμων (taken from Philip Wesley Comfort and David P. Barrett, The Text of the Earliest New Testament Greek Manuscripts, 2 vols. [3d ed; Grand Rapids, Mich.: Kregel Academic, 2019], 1:237)

. . . Then come together again so that Satan will not tempt you . . .