Bemidbar 9:2 - Why is the word pronounced "Posach", with a kamatz?

Question

During this morning's (4th day Hol Hamo'ed Pesach outside Israel) I noticed that in Numbers 9:2:

וְיַעֲשׂ֧וּ בְנֵי־יִשְׂרָאֵ֛ל אֶת־הַפָּ֖סַח בְּמוֹעֲדֽוֹ׃

’Let the children of Israel keep the passover in its appointed season.

The word "Pesach" which usually has a segol has a kamatz in this case. I know that usually a segol becomes a kamatz on a etnachta and sof pasuk. As you can see, in the above verse, the change is on the tipcha.

None of the standard sommentaries (Mikra'ot Gedolot) explain this anomaly. Is there anyone that (can) explain why the kamatz is here?

Answer 1

Pausal forms don't always come on Etnachta or Silluk, though those are good examples of where a strong pause might be. Sometimes they come on second order disjunctives, like Zakef (Genesis 11:3, Ruth 4:18,22) or Tipcha (Genesis 23:11, Shemot 33:14) or Shalshelet (Vayikra 8:23).

Here this is especially reasonable as the verse is such that the Tipcha on פסח marks the strongest division in the verse. In longer verses the major pauses are usually on Zekefim so a pausal form on a Tipcha would be unlikely.