Now if Christ is preached that He has been raised from the dead, how do some among you say that there is no resurrection of the dead? But if there is no resurrection of the dead, then Christ is not risen. And if Christ is not risen, then our preaching is empty and your faith is also empty. Yes, and we are found false witnesses of God, because we have testified of God that He raised up Christ, whom He did not raise up—if in fact the dead do not rise. For if the dead do not rise, then Christ is not risen. And if Christ is not risen, your faith is futile; you are still in your sins! Then also those who have fallen asleep in Christ have perished – 1 Corinthians 15:12-18
Paul is not saying that the dead are in Heaven with Jesus. What he is saying is if there is no such thing as the resurrection of the dead then we are doomed because it would also mean that Jesus Himself was not raised from the dead either. This means that when we die, that ‘s it. It’s all over. We will remain in our graves and those who are alive have no hope because if Jesus was not raised from the dead that means that there will be no second coming. It is at the second coming that those who fell asleep in Christ will rise and be gathered to Him and then those who are still alive will join them. Our friends and loved ones who died in Christ will not be with Him before He comes again. Like King David, they are asleep in their graves.
We can rest assured that Jesus was raised from the dead. We have the empty tomb to prove this. He is now in Heaven with the Father fulfilling His role as our High Priest until the day comes when He will descend with the angels to gather His elect. Until then, let us watch and wait in faith.