Wanneer begint de dag

http://www.isawthelightministries.com/daystarts.html
https://judaism.stackexchange.com/questions/69630/how-to-reconcile-if-when-the-jewish-day-was-to-begin-at-sunset
https://judaism.stackexchange.com/questions/47635/is-there-really-evidence-that-the-rabbis-changed-the-days-beginning-from-sunris
https://thetorah.com/does-a-day-begin-in-the-evening/

Nieuwe Testament Grieks

http://www.isawthelightministries.com/resurrectiontime.html

G3796 opse, ὀψέ late

From the same as opiso (through the idea of backwardness);
(adverbially) late in the day;
by extension, after the close of the day -- (at) even, in the end.

G3798 opsios, ὄψιος, ὀψία, ὀψιον (ὀψέ) evening

From opse; late; feminine (as noun) afternoon (early eve)
or nightfall (later eve) -- even(-ing, (-tide)).

https://pcg.church/articles/273/when-does-your-day-begin

An account in Acts can also be used to clarify the beginning of the day. “And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight. And there were many lights in the upper chamber, where they were gathered together” (Acts 20:7-8).

Act 27:27 “And when the fourteenth night came, as we were driven up and down in the Adriatic Sea, about midnight the sailors suspected that they were drawing near some land.”

Act 27:33 And when day was about to come , Sha’ul urged them all to take food, saying, 'Today is the fourteenth day you have continued without food, and eaten none at all.'“

Oude Testament

https://pcg.church/articles/273/when-does-your-day-begin

Psa 55:10 יוֹמָ֤ם H3119 yo·Mam Day וָלַ֗יְלָה H3915 va·Lay·lah, and night יְסוֹבְבֻ֥הָ H5437 ye·sov·Vu·ha they go about עַל־ H5921 'al- her upon חוֹמֹתֶ֑יהָ H2346 cho·mo·Tei·ha; it upon the walls וְאָ֖וֶן H205 ve·'A·ven thereof mischief וְעָמָ֣ל H5999 ve·'a·Mal also and sorrow בְּקִרְבָּֽהּ׃ H7130 be·kir·Bah. [are] in the midst

Psa 55:17 עֶ֤רֶב H6153 'E·rev Evening וָבֹ֣קֶר H1242 va·Vo·ker and morning וְ֭צָהֳרַיִם H6672 Ve·tzo·ho·ra·yim and at noon אָשִׂ֣יחָה H7878 'a·Si·chah will I pray וְאֶהֱמֶ֑ה H1993 ve·'e·he·Meh; and cry aloud וַיִּשְׁמַ֥ע H8085 vai·yish·Ma' and he shall hear קוֹלִֽי׃ H6963 ko·Li. my voice

King David sets us an example of prayer in Psalm 55:17, but not only that—he recognized when the day begins: “Evening, and morning, and at noon, will I pray ….”