Hosea 12:9

‘But I am YHWH your God from the land of Egypt, I will yet again make you to dwell in tents, as in the days of the solemn feast.'

In reply YHWH reminded them of Who He was. He was not a comfortable Canaanite god. He was a wandering God and a tent-dweller (compare 2 Samuel 7:6). He was YHWH their God from the land of Egypt, the One Who had accompanied them there and had been with them there in their distress, Who had delivered them through the Red Sea and accompanied them through the wilderness where they had dwelt in tents, as He also had. This was something that they remembered yearly at the Feast of Booths (Tabernacles) when they celebrated the end of the harvest season and remembered their delivery from Egypt. It had been prior to their entering the land, and building for themselves grand houses. Now His warning was that He would ‘yet again make you to dwell in tents' (outside the land is assumed). It was an indication that they would shortly be taken back into wilderness days by being taken into exile where they would have to live in crude accommodation.

‘As in the days of the solemn feast.' There may have been a double meaning here, referring on the one hand to their solemn feasts at Sinai, continuing on in the Tabernacle once it had been erected, and on the other to the regular feast of Tabernacles when they dwelt in booths (or if that was not being observed in that way at some other such feast. For when huge numbers gathered at small cities living in tents would be essential.).