Question: Please explain the 2nd Samuel 24:1 verse and another one that puzzles me 2 Samuel 24:24 and 1st Chronicles 21:24-26.
Response: The other passage to add to the mix here is 1st Chronicles 21:1, where we are told that it was Satan who incited David to conduct the census. Both of these pairs of passages are examples of instances where Chronicles provides us with additional information, something it often does, even though it is more synoptic than Samuel (covering, as it does, Jewish history from the beginning [by way of genealogy] to the decree of Cyrus marking the beginning of the end of the Babylonian exile). The price "discrepancy" of 50 shekels in Samuel and 600 in Chronicles is only apparent (cf. the "NIV Study Bible" note in loc. 1Chron.21:25). The Samuel price is only for the oxen and their equipment (cf. Ex.21:32: the price of a gored slave being 30 shekels of silver; also cf. Gen.37:28), while the Chronicles' price is only for the land (which, incidentally, became the site of the temple). The way the Samuel passage is written in the Hebrew, it is very easy to take the 50 shekels as payment for land and animals, but also possible (and preferable) to translate ... "so he bought the threshing floor [price not disclosed], and the oxen [he bought] for 50 shekels of silver". Chronicles gives us the additional information that the place (i.e., the maqom, not just the threshing floor and no mention of oxen) cost David much more: 600 gold shekels. Now in Greek times, a ratio of 12:1 silver to gold was common, and such a comparison here would yield a price for the land 144 times more costly than that for the oxen and gear. This makes sense as a price for the future temple site and full value exchange (generously estimated) for Araunah's ancestral possession.
On the census, first, numbering within the Lord's holy nation was an act not to be taken lightly, because, in doing so, one "set apart" or "sanctified" those so numbered. A redemption price for those counted was thus required (Ex.30:1-11), for, obviously, none of us is pure enough to stand before the Lord on our own works - we have to have someone "pay the price" for us (a type of the redemptive work of Jesus Christ: 1Pet.1:18-19; and cf.1Cor.6:20; 7:23; Gal.4:5; Tit.2:14; 2Pet.2:1 etc.). Therefore, conducting an unauthorized census within Israel (and one without redemption) invited the Lord's scrutiny or "visitation", a terrifying prospect under the best of circumstances, and doubly so here for it was for the sins of the nation that the Lord instigated this process in the first place. It is no accident that what stops the plague in the end is David's costly sacrifice on the future temple mount, a symbolic foretaste of all the other symbolic sacrifices which would also presage our Lord's ultimate, efficacious and real sacrifice for all mankind which was to end the plague of death forever for all who would turn to Him.
As to the role of the devil in this process, we may say that all things are under God's control and that He is free to utilize any and all creature activity to further His own righteous ends. Therefore, the fact that God and Satan are mentioned as "instigators" in the respective books is not contradictory. We see this sort of thing in our own lives too, for what believer is there who has never experienced God's deliverance and ultimate good flowing from what had originally been our own faithless acts (He works everything out for the good of those who love Him: Rom.8:28)? Everything that happens in history is part of the ordained plan and will of God, so that such instances are innumerable. Other specific examples in the Bible of God using, in particular, the activities of evil spirits to further His own ends include:
a. God's permissive testing of Job (Job 1:12; 2:6).
b. The evil spirit sent by God to Abimelech and the citizens of Shechem (Jdg. 9:23).
c. The evil spirit from the Lord who vexes Saul (1Sam.16:14; 18:10).
d. Micah's story of the evil spirit who volunteers to deceive the king (1Ki.22:19-23).
e. The unleashing of demonic forces to warn and to punish the earth during the tribulation (Rev.9:1-19).
See section III.5 of the Satanic Rebellion: Part 4 for more details on this last point.
Hope this gets to the nub of your questions.
Yours in Christ,