Reference for Avodah Zarah 35:13

יצאה בת קול ואמרה רבי חנינא בן תרדיון וקלצטונירי מזומנין הן לחיי העולם הבא בכה רבי ואמר יש קונה עולמו בשעה אחת ויש קונה עולמו בכמה שנים

“Yes,” he replied. “Then swear to me.” He swore to him. He thereupon increased the flame and removed the tufts of wool from over his heart, and his soul departed speedily. The Executioner then jumped and threw himself into the fire. And a heavenly voice came forth and exclaimed: R. Hanina b. Teradion and the Executioner are invited to life in the world to come. Rabbi wept and said: One may acquire eternal life in a single hour, another after many years.

Jastrow