“fourth.” Although the Masoretic Hebrew text reads, “seventh,” that creates a contradiction in the text with such verses as Judges 14:17. The Septuagint and some Aramaic texts read “fourth,” and there is every reason to believe that was the original reading of the Hebrew. There is only a difference of one letter between the Hebrew word for “fourth” and “seventh,” and that could have been made by an accidental scribal error.
“we will burn you and your father’s house with fire.” The intensity of the Philistine's demand and threat show the value of 30 complete sets of clothing including the undergarment and the outer garment. It was significant enough an expense that the Philistines charged the woman and her family with colluding with Samson to take their belongings and thus enrich themselves.
“Have you all called us.” The verb is plural in Hebrew, thus meaning, “Have you all called us?” Because the sentence starts with the Philistines speaking to Samson’s wife, we would naturally assume that the “you” in the last phrase was singular, referring to just the wife. But it is plural, and indicates that at this point, the Philistine leaders thought that the Timnite woman had sided with the Israelites against them and that “you all” (she, Samson, and her family) had plotted together to take their property, and so they thought killing the Timnite and her family as national enemies was justified.