How true. The OP is seeking Christian’s explanation on the justice of God which he has problem in reconciling it with the killing verses in Ezekiel 15 and 1 Samuel 5 .
As for the OP, famidgy, I would like to draw your attention to some of the explanations by some posters here which are relevant and may answer your question about the justice of God in Christians’ understanding.
You may not agree with this as this is purely Christianity concept but I wish to add that God’s justice all began with his plan for salvation of humankind to bring them back to his presence as when he first created them. This began with the creation and when Adam fall because of disobedience and sin.
You see unlike Islam, in Christianity, God act through the history of him and his people. In other word, he works for the bigger picture which very often we human are unable to see. Otherwise how can you explain then that there were good people being killed in natural disaster like tsunami and earthquake?
There were Christians who were martyred because of their belief in God. They were killed and knew they would be killed because they did not want to forsake their religion. Not mention diseases and plagues that consume evil and good people alike.
Thus physical death is not the parameter for God’s justice. Christians are taught that they are merely ‘permanent residence’ on this earth and that their real citizenship is in heaven.
Therefore God’s justice does not end on earth but at the last judgment. If we want to question his justice it will have to be brought up there with him. Challenge him why he convicts you to hell if you have done all that is required for eternal life. Of course we know he is a just God, he will not waver in his justice.
However for God to be just he has to operate within his own law otherwise where would be the justice? God being the truth he has to be true to himself. Like secular government, if the law says that one should pay when committing a particular traffic offence, the judge simply cannot set the offender free unless the fine is paid. It does not matter from where the money comes from but the fine must be paid before he is let off the hook. Similarly with God, the price must be paid for sin.
The price of sin is death – this death is the absence of eternal life. In other word God justice demands that if you sin you would go to hell; if you don’t you will go to heaven. Who knows, those innocent women and children that were being killed in Ezekiel 15 and 1 Samuel 5, they might just go to heaven like the Christian martyrs and all good people who died in similar circumstances, which is certainly much better for them.
But you see, God works for the bigger picture and true to his promise as being prophesized, culminating in the coming of his son, Jesus Christ.