The 4 living creatures and the 24 elders

[bobietan]

I need an explanation the 4 living creatures and the 24 elders mention in the book of Revelations

 

[Fidelis]

Here is an excerpt from the Navarre Bible Commentary on the Book of Revelation (singular, not plural, BTW), chapter 4:

1. God’s sovereignty over the world–as symbolized by the throne–is
   shared in by others whom the vision also portrays as seated on thrones.
   They are symbolically described as twenty-four elders who act as a kind
   of heavenly council or senate. These elders appear frequently in the
   course of the book, always positioned beside God, rendering him tribute
   of glory and worship (cf. 4:10; 5:9; 19:4), offering him the prayers of
   the faithful (cf. 5:8) or explaining events to the seer (cf. 5:5; 7:13).
   It is not clear whether they stand for angels or saints; the Fathers and
   recent commentators offer both interpretations.

The symbolic number (twenty-four) and the way they are described suggest
that they stand for saints in the glory of heaven. They are twenty-four
–twelve plus twelve, that is, the number of the tribes of Israel plus
that of the Apostles. Our Lord in fact promised the latter that they
would sit on thrones (cf. Mt 19:28). The twenty-four elders, then,
would represent the heavenly Church, which includes the old and the new
Israel and which, in heaven, renders God the tribute of perfect praise
and intercedes for the Church on earth. The number twenty-four has also
been seen as reflecting the twenty-four priestly classes of Judaism,
thereby emphasizing the liturgical dimension of heaven (cf. 1 Chron 24:
7-18; 25:1, 9-13). Whichever is the case, the white garments indicate
that they have achieved everlasting salvation (cf. 3:5); and the golden
crowns stand for the reward they have earned (cf. 2:10), or the
prominence among Christians, who have been promised that, if they come
out victorious, they will sit on Christ’s throne (cf. 3:21).

The author of the Book of Revelation avails of images used by the
prophets to describe the glory of Yahweh. The four living creatures are
very like those in the prophet Ezekiel’s vision of the chariot of the
Lord drawn by four angels representing intelligence, nobility, strength
and agility (cf. Ezek 1:10; 10:12; Is 6:2).

Christian tradition going back as far as St Irenaeus has interpreted
these four creatures as standing for the four evangelists because they
“carry” Jesus Christ to men. The one with the face of a man is St
Matthew, who starts his book with the human genealogy of Christ; the
lion stands for St Mark: his Gospel begins with the voice crying in the
wilderness (which is where the lion’s roar can be heard); the ox is a
reference to the sacrifices in the temple of Jerusalem, which is where
St Luke begins his account of Christ’s life, and the eagle represents
St John, who soars to the heights to contemplate the divinity of the
Word.

For more on the Book of Revelation (also called the Apocalypse), see here:
catholic.com/thisrock/2002/0209fea5.asp
catholic.com/thisrock/1995/9510ntg.asp