Definition and Context:
The phrase "a land not theirs" refers to the concept of a foreign land or territory that is not originally owned or inhabited by a particular group of people. In the biblical context, this phrase is often associated with the experiences of the Israelites, particularly in relation to their sojourn in Egypt and the subsequent promise of the land of Canaan.

Biblical References:

1. Genesis 15:13 :
"Then the LORD said to Abram, 'Know for certain that your descendants will be strangers in a land not their own, where they will be enslaved and oppressed for four hundred years.'"

· Context: This verse is part of God's covenant with Abram (later Abraham), where God foretells the future of Abram's descendants. The "land not theirs" refers to Egypt, where the Israelites would live as foreigners and eventually become enslaved.

2. Exodus 1:8-14 :
This passage describes the Israelites' oppression in Egypt under a new Pharaoh who did not know Joseph. The Israelites, living in a land not their own, were subjected to harsh labor and oppression.

3. Acts 7:6 :
"God spoke to this effect: 'That his descendants would be strangers in a foreign land, and that they would be enslaved and mistreated for four hundred years.'"

· Context: In Stephen's speech before the Sanhedrin, he recounts the history of Israel, including the prophecy given to Abraham about his descendants living in a foreign land. This reiterates the theme of the Israelites' sojourn in Egypt.

Theological Significance:

· Covenant and Promise: The concept of living in "a land not theirs" is closely tied to the Abrahamic covenant. Despite the temporary displacement and suffering, God promises deliverance and the eventual inheritance of the Promised Land, Canaan.

· Faith and Perseverance: The experience of living in a foreign land serves as a test of faith and perseverance for the Israelites. It highlights the importance of trusting in God's promises despite present hardships.

· Typology and Foreshadowing: The sojourn in Egypt and the subsequent exodus serve as a typology for spiritual deliverance. Just as the Israelites were delivered from physical bondage, the New Testament draws parallels to spiritual liberation through Christ.

Historical and Cultural Context:

· Egyptian Sojourn: Historically, the Israelites' time in Egypt is marked by both prosperity and suffering. Initially welcomed during Joseph's time, they later faced enslavement as their population grew and threatened the Egyptian rulers.

· Cultural Identity: Living in a land not their own, the Israelites maintained their distinct cultural and religious identity, which was crucial for their survival and eventual return to the Promised Land.

Related Concepts:

· Exile and Return: The theme of exile, seen later in the Babylonian captivity, echoes the experience of living in a land not theirs. Both instances emphasize God's faithfulness in restoring His people.

· Pilgrimage and Sojourning: The idea of being a sojourner or pilgrim in a foreign land is a recurring biblical motif, symbolizing the transient nature of earthly life and the hope of a heavenly homeland.

Conclusion:
The phrase "a land not theirs" encapsulates a significant aspect of the Israelite narrative, reflecting themes of covenant, faith, and divine promise. It serves as a reminder of God's sovereignty and the ultimate fulfillment of His promises to His people.