Revelation 7:7

tribe of Simeon
The second son of Jacob by Leah (Gen. Gen. 29:33). Simeon means hearing.

tribe of Levi
The third son of Jacob by Leah (Gen. Gen. 29:34). Levi means attached, or joined.

tribe of Issachar
The ninth son of Jacob by Leah (Gen. Gen. 30:18). Issachar means he will bring a reward.
Read Revelation 7:7