The term eager
can also be translated as get up early.
Therefore, another way of understanding the last line of Zephaniah 3:7 is, But they got up early, they made corrupt all their actions.
The sense is that the people of Jerusalem were eager to engage in sinful activities; they ran toward evil.
Scripture contrasts such an attitude with the Lord, who is pictured by Jeremiah as zealously rising early to warn his people by the prophets (Jeremiah 7:13, Jeremiah 7:25; Jeremiah 11:7; Jeremiah 25:3; Jeremiah 26:5; Jeremiah 29:19; Jeremiah 32:33; Jeremiah 35:14–15; Jeremiah 44:4). Motyer’s words are to the point: "What a tragedy! Yet one so often lived out—the Lord up and about, ready to meet with us (Isaiah 50:4); we, eagerly out of bed to pursue, at best, our own way or, at worst, to corrupt all our doings. The Lord, awaiting our fellowship and left disappointed!”1
7 I said, ‘Surely you will fear me; you will accept correction. Then your dwelling would not be cut off according to all that I have appointed against you.’ But all the more they were eager to make all their deeds corrupt.