In 1 Sam. 2 the man of God comes to Eli with a horrifying pronouncement. Eli's family was to be removed from the priesthood; none of his descendants were to live to old age, and his two sons were both to die on the same day. This would happen because Eli had not reined in his wicked sons and their perversion of the worship of God. Then, in chapter 3, the first message received by Samuel as a child prophet is essentially a repeat with one addition: "And therefore I have sworn unto the house of Eli, that the iniquity of Eli's house shall not be expiated with sacrifice nor offering forever." (1 Sam. 3:14) Why the repeat? Why the later statement that sacrifice would not work as a means to avoid the punishment?
A similar thing happens later with King Saul. In chapter 13, because of the sin with the offering, Saul is told that the kingdom would be removed from him and given to a man after God's heart. Then in chapter 15 he is reminded that he was anointed at God's command and that he should listen to God. After he fails to obey God's instructions against the Amelekites, Saul is again told the kingdom would be taken away from him. This time God instructs Samuel to quit praying for Saul (16:1).
Why did God repeat his pronouncements against Eli and Saul? I think in each case God was letting Eli or Saul know what was coming because of their sins and allowing them a chance to repent. It is spoken as a done deal but is actually more of a warning. We see this same kind of judgment declared against Nineveh in the book of Jonah. Jonah's message was simply "Yet forty days and Nineveh shall be overthrown" (3:4) and yet when the city repented, God relented. Jonah was so aware of God's mercy that he had expected it. In all three cases we see bald statements of doom without an "unless", but it seems that in each case God was allowing for repentance. Why else repeat the judgment to Eli and Saul? And so we see a lesson of God's mercy.
There is also another lesson here. When Eli and Saul refused to correct the error of their ways God reached a point at which He would no longer show mercy. Eli is told that sacrifices would no longer expiate the sins of his house and Samuel is told to stop mourning for Saul. Their sins had reached a point at which God would no longer remove the earthly consequences of those sins. So, while we see the mercy of God, we also see a warning. Do not keep flirting with sin until God decides you are a lost cause.
Rom. 11:22 "Behold then the goodness and severity of God: toward them that fell, severity; but toward thee, God's goodness, if thou continue in his goodness: otherwise thou also shalt be cut off."
Lucas Ward