“and the land has become defiled.” One of the great lessons of the Bible is that the behavior of people affects the land that they live on. The land that we humans live on is not “neutral territory,” unaffected by what the people do. The land and weather are affected by God and by demons, and demons work to make the land unproductive and life on the land harsh, frustrating, and challenging. Every farmer knows how frustrating and hurtful it is to plant crops and then have them die from lack of rain. But rain in its season and productive soil are promises of God for the people who live on the land if they live godly lives (cp. Deut. 28:1-2, 8, 11-12), and if people abandon God then demons come in and make the weather destructive and the land unproductive, as we see here in Leviticus 18:25.
People want good weather with regular, gentle rains, plenty of sunshine, and no destructive weather such as hurricanes or tornados, and certainly no famines, so they should live godly lives. Furthermore, although a godly person living in a sinful land can be protected to some extent, if there is a hurricane or famine, even the godly person will be affected. That is why Christians must stand up against those who promote ungodly behavior, and why a nation must have godly laws and leaders if it is to do well. This lesson about people’s behavior affecting the land is throughout the Old Testament (cp. Deut. 11:13-17; 28:1, 12, 15, 22-25, 38-40; Lev. 18:24-25; Ps. 107:33-34; Jer. 3:2-3; 9:10-14; 12:4; 23:10; Amos 4:6-10).
“I have visited its iniquity upon it.” For more on the meaning of “visit,” see commentary on Exodus 32:34. The word “visit” can also in some contexts be translated “punish,” and so the sentence could also be translated as it is translated in the CSB: “The land has become defiled, so I am punishing it for its sin.”