Quoting Commentary for Obadiah 1:2

AND MOAB WAS SORE AFRAID OF THE PEOPLE. The meaning of this is [that Moab stood in great fear] because they [the Israelites] were many,¹The Hebrew text reads: ki rav hu. This can be interpreted as “although they were many,” in which case the reference would be to the Moabites, [the word ki meaning “although”]. The meaning of the verse would thus be: “And Moab was sore afraid of the Israelites although they [the Moabites] were many, Ramban, wishing to exclude this interpretation, for the reason cited in the text, explains that the word ki here means “because”; hence the pronoun hu — “they” [they were many] refers to the Israelites. for Moab was small among the nations;²See Obadiah 1:2. and it was not an ancient people, like the Canaanites, the Amorites and other [nations of the] sons of Noah. Therefore they [the Moabites] were greatly afraid of the people who outnumbered them exceedingly, for they were fruitful, and increased abundantly, and waxed³Exodus 1:7. greater than the Moabites. And they were furthermore overcome with dread because of the children of Israel,⁴Verse 3 here. — Hence the double expression of the verse: And Moab was sore afraid … and Moab was overcome with dread. for they had heard of the great wonders that had happened to them and their fathers. Now Moab knew that Israel would not take their land from them, since they had sent to them [offering peace]⁵Judges 11:17: And in like manner he sent unto the king of Moab … just as they had sent to Sihon, [asking permission only to pass through their land], saying, until I shall pass over the Jordan into the Land which the Eternal our G-d giveth us.⁶Deuteronomy 2:29. Or it is also possible that they had heard of G-d’s prohibition, when He said to the Israelites, Be not at enmity with Moab.⁷Ibid., Verse 9. Therefore they said to the elders of Midian: “Even though the Israelites will not capture our land, they will lick up because of their great numbers all that is round about us, as the ox licketh up the grass of the field,⁸Verse 4 here. and they will capture all [the lands] that surround us, just as they did to the two Amorite kings, and they will make us servants to do taskwork.”⁹Joshua 16:10.

small A small and despised kingdom, as he calls it above one small horn, and that is in the manner of (Obad. 1:2): “...you are very despised.”

According to Midrash Tanchuma Ki Teytze 10 the words: “and he did not fear G’d,” mean that the people of Amalek (descendants of Esau) had a tradition that they could be defeated only by descendants of Rachel seeing that we have a verse in Jeremiah 49,20 אם לא יסחבום צעירי הצאן, “(hear then the plan G’d has devised against Edom) surely the shepherd boys shall drag them away.” These latter words are understood to refer to the youngest of the tribes of Israel, the ones which have been described as נער, (compare Genesis 37,2 where Joseph is described in these terms). We find that also Edom is described as junior in Ovadiah 2, קטן, “junior,” and it is appropriate that a junior such as Edom be defeated by another junior. The reason is that Joseph who attained prominence and remained loyal to G’d although in the environment of two sinners (Pharaoh and Potiphar) without learning from their deeds, is so superior to Esau who grew up between two righteous people (Yitzchak and Avraham) and still did not learn from the good deeds of those righteous people. The Torah testifies that Joseph said: “I fear the Lord,” (Genesis 44,18) as opposed to Amalek. No wonder that the one was doomed to fall by the hand of the other. [If Moses chose the נער Joshua to battle Amalek this was because he was a descendant of Ephrayim, a son of Joseph. Ed.]

And a contemptible person will stand on his base Then the kingdom of Rome will strengthen itself on its stand, as it says (Obad. 1:2): “you are very despised,” and the Romans will rise and take the kingdom from the Greeks.

בלא עם [I WILL MOVE THEM TO JEALOUSY] WITH THOSE WHO ARE NOT A PEOPLE — i.e. with a nation that has no reputation, as it states e.g. of the Chaldeans (Isaiah 23:13), “Behold, the land of the Chaldeans, this people was not; [the Assyrians founded it …]”, and of Esau it states (Obadia 1:2) “Thou art greatly despicable”.