Why Are We Supposed to Love as God Loves but Not Condemn as He Condemns?

Questions about why we’re supposed to love as God loves but not condemn as he condemns, whether Jesus would have issued a command like 1 Samuel 15:3, whether it would be kinder to not tell people the gospel so they can be judged by their hearts and works, and why God destroyed the world in the flood if he knew there was a salvation plan.

• If we’re supposed to love as God loves, loving those who do us wrong, why don’t we follow his example when he eternally damns those who hate or reject him?
• Would Jesus have issued a command like 1 Samuel 15:3?
• If those who haven’t heard of Jesus get judged on their hearts and their works, then wouldn’t it be kinder to not tell them the gospel so it’s easier for them to qualify for the afterlife?
• Why did God choose to destroy the world in the flood so early on when he knew the salvation plan from before the beginning?