Two separate questions here.
1) Petruchio is late for his own wedding, and he turns up outrageously dressed long after the allotted time. Baptista, Katharina's father says to him as he arrives:
Why, sir, you know this is your wedding-day:
First were we sad, fearing you would not come;
Now sadder, that you come so unprovided.
2) Petruchio convinces Katharina to say the sun is the moon. Depending on how you read it, this can be lots of different things: either a statement of his own dominating, masculine control, a statement about how useless and worthless language is (Petruchio, of course, re-names Katharina "Kate" right at the start!), or a silly game that he wants Katharina to play.
As with so many other things about this difficult, problematic play, the critical jury is still very much out - nobody agrees!