See this passage explained in the notes at Matthew 15:32-39.

Mark 8:1

In those days - While in the wilderness, where he had cured the deaf-mute man.

Having nothing to eat - Having come unprovided, or having consumed what they had brought.

The multitude being very great - Or rather, There was again a great multitude. Instead of παμπολλου, very great, I read παλιν πολλου, again a great, which is the reading of BDGLM, fourteen others, all the Arabic, Coptic, Ethiopic, Armenian, Gothic, Vulgate, and Itala, and of many Evangelistaria. Griesbach approves of this reading. There had been such a multitude gathered together once before, who were fed in the same way. See Mark 6:34, etc.

In those days,.... The Ethiopic version reads, on that day; as if it was on the same day that the deaf man was healed; and so it might be; and on the third day from Christ's coming into those parts; and so is very properly expressed, "in those days"; see Mark 7:31, compared with the following verse:

the multitude being very great: for the number of men that ate, when the following miracle was wrought, were about four thousand; see Mark 8:9. The Vulgate Latin, Arabic, and Ethiopic versions add, "again"; referring to the former miracle of the five thousand, who were fed with five loaves, and two fishes, Mark 6:44.

And having nothing to eat; what they might have brought with them being expended, and they in a desert, where nothing was to be had, nor bought for money:

Jesus called his disciples to him, and saith unto them; See Gill on Matthew 15:32.

In those days the multitude being very great, and having nothing to eat, Jesus called his disciples unto him, and saith unto them,

8:1 In the Coasts of Caesarea Philippi

SUMMARY OF MARK 8:

The Four Thousand Fed. At Dalmanutha. Seeking a Sign from Heaven. The Blind Man Healed at Bethsaida. Peter's Confession at Caesarea Philippi. The Death and Burial of the Son of Man. Peter Rebuked. Taking the Cross and Following Christ.

In those days. While Christ was in Decapolis. For notes on the feeding of the four thousand, see Mt 15:32-38. This is not the same event as the feeding of the five thousand (Mt 14:13-21 Mr 6:32-44 Lu 9:10-17 Joh 6:1-14). The Lord refers to both miracles, in Mr 8:19,20.

8:1 Mt 15:32.

CHAPTER 8

Mr 8:1-26. Four Thousand Miraculously Fed-A Sign from Heaven Sought and Refused-The Leaven of the Pharisees and Sadducees-A Blind Man at Bethsaida Restored to Sight. ( = Mt 15:32-16:12).

This section of miscellaneous matter evidently follows the preceding one in point of time, as will be seen by observing how it is introduced by Matthew.

Feeding of the Four Thousand (Mr 8:1-9).

1. In those days the multitude being very great, &c.

8:1-10 Our Lord Jesus encouraged the meanest to come to him for life and grace. Christ knows and considers our frames. The bounty of Christ is always ready; to show that, he repeated this miracle. His favours are renewed, as our wants and necessities are. And those need not fear want, who have Christ to live upon by faith, and do so with thanksgiving.