3. But God said. The emphasis is on the word “God,” in contrast with the “I” in 2: “As for me, I had in mine heart to build.” To build a house for the Lord was a worthy purpose, but God had reasons why it would be better for someone other than David to build the Temple.
Man of war. It was hardly appropriate that a man of war should build the world’s great temple of peace. The wars of David were perhaps necessary and justifiable wars, but they were wars nevertheless, and they resulted in the shedding of much blood. It seemed inappropriate that such a ruler should build the Temple (see 22:8).