Biblical Context:
The account of David building an altar is primarily found in 2 Samuel 24 and 1 Chronicles 21. This event occurs towards the end of David's reign and is a significant moment in his life, reflecting themes of repentance, obedience, and worship.

Narrative Summary:
The narrative begins with David's decision to conduct a census of Israel and Judah, an act that displeased God. Despite Joab's objections, David insisted on numbering the people. As a result, God sent a plague upon Israel as a judgment for David's sin. In response to David's plea for mercy, God instructed the prophet Gad to tell David to build an altar on the threshing floor of Araunah the Jebusite.

Key Verses:
· 2 Samuel 24:18-19 : "That day Gad came to David and said to him, 'Go up and build an altar to the LORD on the threshing floor of Araunah the Jebusite.' So David went up at the word of Gad, just as the LORD had commanded."
· 1 Chronicles 21:26 : "And David built an altar to the LORD there and offered burnt offerings and peace offerings. He called on the LORD, and He answered him with fire from heaven on the altar of burnt offering."

Theological Significance:
1. Repentance and Atonement: David's construction of the altar is an act of repentance and a means of atonement for his sin of conducting the census. It underscores the importance of obedience to God's commands and the necessity of seeking His forgiveness.

2. Divine Mercy: The cessation of the plague following David's sacrifice highlights God's mercy and readiness to forgive those who earnestly seek Him. It demonstrates that God desires repentance and is willing to restore His people when they turn back to Him.

3. Worship and Sacrifice: The altar represents a place of worship and sacrifice, central themes in the life of Israel. David's willingness to purchase the threshing floor at full price, despite Araunah's offer to give it freely, illustrates the principle that true worship involves personal cost and sacrifice.

4. Foreshadowing the Temple: The site of the altar, the threshing floor of Araunah, later becomes the location for Solomon's Temple (2 Chronicles 3:1). This connection emphasizes the continuity of God's plan and the significance of the site in Israel's worship history.

Historical and Cultural Context:
Threshing floors were open spaces used for separating grain from chaff, often located on elevated ground to catch the wind. Araunah's threshing floor, situated on Mount Moriah, held historical and spiritual significance, being associated with Abraham's near-sacrifice of Isaac (Genesis 22).

Lessons for Believers:
David's experience teaches believers about the seriousness of sin, the importance of obedience, and the power of genuine repentance. It also highlights the necessity of worship and sacrifice in the believer's relationship with God. David's actions remind Christians of the cost of discipleship and the call to honor God with their resources and lives.