And Moses and Eleazar the priest received the gold from the commanders of thousands and of hundreds, and brought it into the tent of meeting, as a memorial for the people of Israel before the Lord.
The significance of this gift is that it came from the army of Israel after God ordered Israel to attack Midian. 12,000 Israelite men were sent off to war. The kings of Midian were captured and killed. Balaam, the false prophet who had enticed Israel against God with sexual sin and idolatry was also killed. They captured Midianite spoils and territory.
After the battles, the officers of the army counted their troops and found that not one Israelite had died in the war against Midian. And it was the overwhelmed grateful hearts of these officers who brought the gift of the spoils of war into the tabernacle.
God commanded the people to eradicate Midian for their evil. He led them in battle and protected them from death. And God was worshiped by the soldiers who fought for Him as they realized God had kept them alive. They saw this offering as a way to recognize the atonement God graciously gave them by sparing all lives in the battle (Numbers 31:50). It was a truly worshipful gift, motivated by the awareness of their unworthiness as sinners and God's great grace in saving their lives.