Post #136 (Lämmchen):
Actually, David stated that he would join his son in the grave – in the assurance that they would both be brought back to life from the grave by resurrection at some time in the future – as God had revealed within the Holy Writings that He had entrusted to the nation of Israel.
You are right. David was a man of his times and knew only what was revealed at the time he said those words. The story goes this way:
2Samuel 12:11 Thus says Jehovah: Your misfortune will rise from your own house! I will take your wives from you and give them to your neighbour who shall lie with them in broad daylight. 12 What you did was done secretly, but what I do will be done before Israel in broad daylight.” 13 David said to Nathan, “I have sinned against Jehovah.” Nathan answered him, “Jehovah has forgiven your sin; you shall not die. 14 However, because you have dared to despise Jehovah by doing such a thing, the child that is born to you shall die.” 15 Then Nathan went to his home.
• Jehovah struck the child that Uriah’s wife had borne to David, and the child became very ill. 16 David entreated God for the child. He kept a strict fast and lay on the ground the whole night. 17 The elders of his house asked him to rise from the ground but he refused. Nor did he join them to eat. 18 On the seventh day, the child died. David’s servants were afraid to tell him that the child was dead for they said, “When the child was still alive, we spoke to him but he would not listen to us. What will he do if we tell him the child is dead?” 19 When David saw his servants whispering to one another, he realised that the child was dead and asked them, “Is the child dead?” They replied, “He is dead.” 20 Then David rose from the ground, washed and anointed himself, and changed his clothes. He entered the house of Jehovah and worshipped. After that, he went to his own house, asked for food and ate. 21 Then his servants asked him, “Why are you acting like this? You fasted and wept for the child while it was alive; but after it died, you got up and took food.” 22 David answered, “While the child was still alive, I fasted and wept, thinking: who knows? Perhaps Jehovah will be kind to me and let my child live. 23 But now that he is dead, why should I fast? Can I bring him back to life? I can go to him but he cannot return to me.” 24 David comforted his wife Bathsheba. He went in and slept with her and she bore a son whom he named Solomon. Jehovah loved him 25 and made it known through Nathan the prophet, who named him Jedidiah on Jehovah’s behalf.