Genesis 2:4-6 meaning

In Genesis 2:4, we see the words Lord God. In the first chapter, God was always referred to as Elohim, the God of power. Here for the first time, God is seen as Yahweh Elohim. Yahweh is the proper name of the one true God. It means "the existing one." Yahweh is sometimes compounded with another word to describe the character of the Lord in greater detail. In this case, Yahweh Elohim (Lord God) means the God of power and perfection, the one who finishes.

At this point, the earth was barren with no plants or rain. Man had not yet been created. Rain is a gift from God, and He can send rain, or He can withhold it. This is clearly illustrated in the book of Amos,

"Furthermore, I withheld the rain from you while there were still three months until harvest. Then I would send rain on one city and on another city, I would not send rain; One part would be rained on, While the part not rained on would dry up"
(Amos 4:7).

The mist that God provided was preparing the ground for vegetation.