The term "coastlands" or "isles" in the Bible often refers to distant lands or regions that are across the sea from the perspective of the Israelites. These terms are frequently used in the prophetic literature of the Old Testament to denote the far-reaching extent of God's sovereignty and the universal scope of His salvation plan. The Hebrew word often translated as "coastlands" is "אִי" (i), which can mean island, coast, or distant land.

Biblical References:

1. Isaiah's Prophecies:
The prophet Isaiah frequently mentions the coastlands in the context of God's judgment and salvation. In Isaiah 42:4, it is written, "He will not grow weak or discouraged until He has established justice on the earth. In His law the coastlands will put their hope." This passage highlights the expectation that even the distant nations will look to the Messiah for justice and hope.

Isaiah 49:1 also calls the coastlands to attention: "Listen to Me, O coastlands, pay attention, you distant peoples. The LORD called Me from the womb; from the body of My mother He named Me." Here, the coastlands are summoned to hear the message of the Servant of the LORD, indicating the global reach of God's redemptive work.

2. Jeremiah's Warnings:
In Jeremiah 25:22, the coastlands are included in the list of nations that will drink the cup of God's wrath: "all the kings of Tyre and Sidon; the kings of the coastlands across the sea." This demonstrates that the coastlands are not exempt from divine judgment and are part of the broader narrative of accountability before God.

3. Ezekiel's Oracles:
Ezekiel 26:15-18 speaks of the coastlands in the context of the fall of Tyre, a major maritime power: "This is what the Lord GOD says to Tyre: 'Will not the coastlands tremble at the sound of your fall, when the wounded groan and slaughter occurs in your midst?'" The coastlands are portrayed as being affected by the downfall of a significant city, emphasizing the interconnectedness of nations.

4. Zephaniah's Vision:
Zephaniah 2:11 prophesies the worship of the LORD by the coastlands: "The LORD will be terrifying to them when He starves all the gods of the earth. Then the nations of the coastlands will bow down to Him, each in its own place." This vision anticipates a time when the coastlands will abandon idolatry and acknowledge the one true God.

Theological Significance:

The mention of the coastlands in the Bible underscores the universal scope of God's plan for humanity. It reflects the biblical theme that God's covenant and promises are not limited to Israel but extend to all nations. The coastlands symbolize the farthest reaches of the known world, illustrating that God's authority and salvation are not confined by geographical boundaries.

In the New Testament, this theme is further developed as the Gospel is preached to all nations, fulfilling the prophetic vision of the Old Testament. The Great Commission in Matthew 28:19, "Therefore go and make disciples of all nations," echoes the call for the coastlands to hear and respond to God's message.

Cultural and Historical Context:

In the ancient Near Eastern context, the coastlands would have been regions accessible by sea, including parts of the Mediterranean basin. These areas were often seen as exotic and distant, representing the ends of the earth from an Israelite perspective. The maritime trade routes connected these regions, facilitating cultural and commercial exchanges, which also made them significant in the biblical narrative as places where God's name would be proclaimed.

The coastlands, therefore, serve as a metaphor for the expansive reach of God's kingdom, inviting all peoples to participate in His redemptive plan.