Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the noble Messenger (peace and blessings be upon him) said: "After entering Paradise, no one would like to come back to the world, even if he were given everything in the world, except the martyr; he will wish to go back to the world and be martyred ten times, because he has seen the honour and dignity (granted to him)."
(b) In al-Tayalisi's narration: "There is no servant who, having attained Paradise from Allah, the Lord of Might, would like to come back to the world, except the martyr; because he will have seen the excellence of martyrdom, he will wish to be martyred ten times."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18517