Question: When the Rapture comes, will all the children be taken also? Or will only the believer’s children be taken? When Israel went into the Promised Land, the heathen’s children were not spared.
Answer: First, it should be realized that children fall into two groups. Those who have not reached the age mentally to be accountable to God who, should they die, would go to Heaven. In Luke 18:15,16 we are told, "They brought unto him also INFANTS...", and Christ said, "...for OF SUCH is the kingdom of God." The age of accountability of a child is known only to God, and varies with the child. Should a baby die now, it is part of the body of Christ, just as it is while living.
1 Corinthians 15:50,51, in speaking of the Rapture says,
"Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.(50) Behold, I shew you a mystery; We shall not all sleep (die), but we shall ALL be changed."
The "all" would include even babies who are also part of the body of Christ. Those children, the second group, that are of the age of accountability will be left behind.
You mention the children of the heathen parents whom God had ordered the Israelites to kill. Those heathen children, under the age of accountability, upon death, would enter the kingdom of God. Had God allowed them to continue, they would have been taught to worship other Gods as their heathen parents did. Thank God for His wisdom and grace. God allowed the children to die, so they could live with Him eternally in His kingdom; instead of allowing the parents to raise them as heathen, destined for an eternal Hell. We need to look at things through God’s eyes, instead of our own.