It doesn't matter if the jews thought of themselves as part of the world just what God thinks and it clearly says what he thought of the world he loved the world enough to do what he did.
Besides that the jews were wrong in their thinking after all how many times did Jesus have to correct them when he was in his ministry?
Yeah, it does matter because that truth is taught throughout the OT. We can begin with just this verse wherein Balaam spoke under and by God's inspiration:
Num 23:8-9
8 "How shall I curse whom God has not cursed?
And how shall I denounce whom the LORD has not denounced?
9 For from the top of the rocks I see him,
And from the hills I behold him;
There! A people dwelling alone,
Not reckoning itself among the nations.
NKJV
And,
Lev 20:24-26
24 But I said to you, "You will possess their land; I will give it to you as an inheritance, a land flowing with milk and honey." I am the LORD your God, who has set you apart from the nations.
Are you still with me? Stay awake. There's more.
Deut 4:19-20
19 And when you look up to the sky and see the sun, the moon and the stars - all the heavenly array - do not be enticed into bowing down to them and worshiping things the LORD your God has apportioned to all the nations under heaven. 20 But as for you, the LORD took you and brought you out of the iron-smelting furnace, out of Egypt, to be the people of his inheritance, as you now are.
NIV
Deut 32:8-9
8 When the Most High gave to the nations their inheritance,
when he divided mankind,
he fixed the borders of the peoples
according to the number of the sons of God.
9 But the Lord's portion is his people,
Jacob his allotted heritage.
ESV
Josh 23:6-13
6 "Be very strong; be careful to obey all that is written in the Book of the Law of Moses, without turning aside to the right or to the left. 7 Do not associate with these nations that remain among you; do not invoke the names of their gods or swear by them. You must not serve them or bow down to them. 8 But you are to hold fast to the LORD your God, as you have until now.
9 "The LORD has driven out before you great and powerful nations; to this day no one has been able to withstand you. 10 One of you routs a thousand, because the LORD your God fights for you, just as he promised. 11 So be very careful to love the LORD your God.
12 "But if you turn away and ally yourselves with the survivors of these nations that remain among you and if you intermarry with them and associate with them, 13 then you may be sure that the LORD your God will no longer drive out these nations before you. Instead, they will become snares and traps for you, whips on your backs and thorns in your eyes, until you perish from this good land, which the LORD your God has given you.
NIV
God drove out His enemies and his people's enemies from the Land.
And one more for good measure:
Ezra 9:1-2
9:1 After these things had been done, the leaders came to me and said, "The people of Israel, including the priests and the Levites, have not kept themselves separate from the neighboring peoples with their detestable practices, like those of the Canaanites, Hittites, Perizzites, Jebusites, Ammonites, Moabites, Egyptians and Amorites. 2 They have taken some of their daughters as wives for themselves and their sons, and have mingled the holy race with the peoples around them. And the leaders and officials have led the way in this unfaithfulness."
NIV
And these passages are just the tip of the iceberg if you're still not convinced. These passages account for why terms like "all" or "world" are frequently used in a limited (qualified) sense in the NT.