Positive commandment · Mitzvat Aseh #200 of 613
To pay a worker his wage on time
ליתן שכר שכיר בזמנו
The verse · Devarim 24:15
בְּיוֹמוֹ תִתֵּן שְׂכָרוֹ וְלֹא־תָבוֹא עָלָיו הַשֶּׁמֶשׁ כִּי עָנִי הוּא וְאֵלָיו הוּא נֹשֵׂא אֶת־נַפְשׁוֹ וְלֹא־יִקְרָא עָלֶיךָ אֶל־ה׳ וְהָיָה בְךָ חֵטְא
“At his day thou shalt give him his hire, neither shall the sun go down upon it; for he is poor, and sets his heart upon it: lest he cry against thee to the Lord, and it be sin in thee.”
The Rambam’s words
To pay a worker his wage on time, as [Deuteronomy 24:15] states: "Pay him his wage on the day it is due."
ליתן שכר שכיר בזמנו, שנאמר: "ביומו תיתן שכרו" (דברים כד,טו).
Who & when
“And this is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Hiring הלכות שכירות