We read this:
Rev 4:7 the first living creature like a lion, the second living creature like an ox, the third living creature with the face of a man, and the fourth living creature like an eagle in flight.

Later we read this:
Rev 6:1 Now I watched when the Lamb opened one of the seven seals, and I heard one of the four living creatures say with a voice like thunder, “Come!”
Rev 6:2 And I looked, and behold, a white horse! And its rider had a bow, and a crown was given to him, and he came out conquering, and to conquer.
Rev 6:3 When he opened the second seal, I heard the second living creature say, “Come!”
Rev 6:4 And out came another horse, bright red. Its rider was permitted to take peace from the earth, so that people should slay one another, and he was given a great sword.
Rev 6:5 When he opened the third seal, I heard the third living creature say, “Come!” And I looked, and behold, a black horse! And its rider had a pair of scales in his hand.
Rev 6:6 And I heard what seemed to be a voice in the midst of the four living creatures, saying, “A quart of wheat for a denarius, and three quarts of barley for a denarius, and do not harm the oil and wine!”
Rev 6:7 When he opened the fourth seal, I heard the voice of the fourth living creature say, “Come!”
Rev 6:8 And I looked, and behold, a pale horse! And its rider's name was Death, and Hades followed him. And they were given authority over a fourth of the earth, to kill with sword and with famine and with pestilence and by wild beasts of the earth.

Has anyone consider a connection between the living creature that speaks and the seal which is opened?