Will we know each other in heaven?
Yes, we will know each other in heaven. Probably the most significant passage in the Bible relating to knowing one another in heaven is found in 2 Samuel 12:22-23,
And he said, “While the child was still alive, I fasted and wept; for I said, ‘Who knows, the LORD may be gracious to me, that the child may live.’ “But now he has died; why should I fast? Can I bring him back again? I shall go to him, but he will not return to me.” (NASB) 2 Samuel 12:22-23
David had sinned by committing adultery with Bathsheba and as a result God took the life of the child (2 Sam. 12:14-15). David goes into mourning and 2 Sam. 12:22-23 reveals David’s agony and the fact that David knew he would see his son some day in heaven.
Another example is the parable of the rich man and Lazarus,
Now it came about that the poor man died and he was carried away by the angels to Abraham’s bosom; and the rich man also died and was buried. “And in Hades he lifted up his eyes, being in torment, and saw Abraham far away, and Lazarus in his bosom. “And he cried out and said, ‘Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water and cool off my tongue; for I am in agony in this flame.’ But Abraham said, ‘Child, remember that during your life you received your good things, and likewise Lazarus bad things; but now he is being comforted here, and you are in agony. (NASB) Luke 16:22-25
Jesus tells us that both men knew each other; one was in heaven and the other in hell. In fact, verse 25 says the rich man had memory of his past. How much we will remember is not mentioned but we will need some memory of the past in order to remember people from this life.
1 Corinthians 13:9-12 implies the same,
For now we see in a mirror dimly, but then face to face; now I know in part, but then I shall know fully just as I also have been fully known. (NASB) 1 Corinthians 13:12
I look forward to seeing my family and friends in heaven, but the most wonderful experience will be to see Jesus,
Then we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air, and thus we shall always be with the Lord. (NASB) 1 Thessalonians 4:17
Praise the Lord!