Once, R. Eliezer was sick, and four elders came to visit him: R. Tarfon, R. Yehoshua, R. Elazar b. Azaryah, and R. Akiva … R. Tarfon responded: "You are more beloved by Israel than the solar orb" … whence we derive that afflictions are beloved (see Sanhedrin 107b)
Four Distinguished Elders Came to Visit Him at His Bedside Rabbi
Mekhilta Tractate Bachodesh 10:12