וַיֶּאֱסֹ֥ף אֹתָ֛ם אֶל־מִשְׁמָ֖ר שְׁלֹ֥שֶׁת יָמִֽים׃
At ibinilanggo niya silang lahat nang magkakasama sa bilangguan sa loob ng tatlong araw.
Ramban
AND HE PUT THEM ALL TOGETHER INTO A WARD THREE DAYS. This he did in order to frighten them and to make them believe that it is G-d he fears,149Verse 18 here. meaning that it is because of his fear of G-d that he is releasing them lest the people of their households perish from hunger. This is the meaning of his words, The rest of you, go and take grain home to your starving households.150Verse 19 here. Besides, they would not have consented to leave the one [Simeon]151See Verse 24. behind except for the purpose of saving all their families.
Radak
ויאסוף, he caused them mental pain without touching their bodies or causing them financial loss.