חֲצֽוֹת־לַ֗יְלָה אָ֭קוּם לְהוֹד֣וֹת לָ֑ךְ עַ֝֗ל מִשְׁפְּטֵ֥י צִדְקֶֽךָ׃
Um Mitternacht steh ich auf, dir zu danken für deine gerechten Vorschriften.
Zohar
Come and behold, King David used to wake up at midnight. And if you might say that he sat or lay down on his bed while reciting these songs and praises, it is not so! Rather, it is as written, "At midnight I will rise to give thanks to You" (Ps. 119:62). "I will rise" definitely means he stood upright as he was occupied with the songs and praises of Torah.