Why did God go to meet him to kill him after he had sent Moses to Egypt.
Because he wavered on The Law after being chosen to receive it.
You asked about Exodus 4:24 (Not Exodus 24 as you corrected when others corrected you):
Here is the passage in question from the Amplified Bible followed by an answer to your question, why did God try to kill Moses:
Exodus 4:
“24 Along the way at a [resting-] place, the Lord met [Moses] and sought to kill him [made him acutely and almost fatally ill].
25 [Now apparently he had [b]failed to circumcise one of his sons, his wife being opposed to it; but seeing his life in such danger] Zipporah took a flint knife and cut off the foreskin of her son and cast it to touch [Moses’] feet, and said, Surely a husband of blood you are to me!
26 When He let [Moses] alone [to recover], Zipporah said, A husband of blood are you because of the circumcision.”
Note about this passage:
Exodus 4:25 He who is on his way to liberate the people of the circumcision has in Midian even neglected to circumcise his second son Eliezer (J.P. Lange, A Commentary). It was necessary that at this stage of Moses’ experience he should learn that God is in earnest when He speaks, and will assuredly perform all that He has threatened (J.G. Murphy, A Commentary on the Book of Exodus).
http://www.biblegateway.com/passage/?search=Exodus%204&version=AMP#fen-AMP-1627b
Maybe someone has already addressed this but the scripture that you gave Exodus 24 does not say anything about God going to kill Moses. Exodus 4:24 does. I think that is why people are confused.