While I am not strongly dispensational in my theology (I believe there is much truth to it), I do agree with many of them that the Bible is PROGRESSIVE REVELATION. Everything was not revealed to the Old Testaments saints. For example, in 2 Samuel 24:1, God is blamed for causing David's temptation. Yet, we New Testament Christians know that God is NOT the source of temptation (James 1:13).
1 Chronicles 24:1, which was written many years later, gives us revelation into the true character behind David's temptation, which is the devil. Why this was not revealed before, we don't know and we could only speculate at this point. However, we do know that many evil things that is attributed to God in the Old Testament were actually works of the devil. Laurence Vance, in his excellent book, "The Other Side of Calvinism" wrote the following:
There is also the matter of God's permission. Often times God is said to do something when in fact he only permitted it to be done. Satan provoked David to number Israel (1 Chr. 21:1), but God was said to do it (2 Sam. 24:1). The best example is Job. Satan was the cause of Job's trouble (Job 1:12, 2:7), but Job (Job 1:21), the writer of Job (Job 42:11), and Satan himself (Job 1:11, 2:5) attributed it to God. This is further confirmed by Charles Hodge: "From these and similar passages, it is evident that it is a familiar scriptural usage, to ascribe to God effects which he allows in his wisdom to come to pass." (The Other Side of Calvinism, p. 273)
Some who know the Hebrew tell us that our English translations place God as a CAUSITIVE AGENT when it should be written to show Him as simply ALLOWING these things.