Albert Barnes Commentary Ezra 1:5

"Then rose up the heads of fathers` [houses] of Judah and Benjamin, and the priests, and the Levites, even all whose spirit God had stirred to go up to build the house of Jehovah which is in Jerusalem." — Ezra 1:5 (ASV)

Only a portion of the Israelites took advantage of the permission of Cyrus. Many remained in Babylon, since they were disinclined to relinquish their property. Those who returned were persons whom God had especially stirred up to make sacrifices for His glory.