Mark 8:6

And he commanded the people to sit down on the ground. In the former feeding they lay down on grass, in this one on the ground. And he took the seven loaves, and gave thanks, and brake. In giving thanks, He has left us an example, that for all gifts conferred on us from heaven we should return thanks to Him. And it is to be remarked, that our Lord did not give the bread to the people, but to His disciples, and the disciples to the people; and gave to his disciples to set before them; and they did set them before the people.

(ubi sup.) For our Lord's breaking the bread means the opening of mysteries; His giving of thanks shows how great a joy He feels in the salvation of the human race; His giving the loaves to His disciples that they might set them before the people, signifies that He assigns the spiritual gifts of knowledge to the Apostles, and that it was His will that by their ministry the food of life should be distributed to the Church.

After the Lord had performed the former miracle concerning the multiplication of the loaves, now again, a fitting occasion presents itself, and He takes the opportunity of working a similar miracle; wherefore it is said, In those days, the multitude being very great, and having nothing to eat, Jesus called his disciples unto him, and, saith unto them, I have compassion on the multitude, because they have now been with me three days, and have nothing to eat. For He did not always work miracles concerning the feeding of the multitude, lest they should follow Him for the sake of food; now therefore He would not have performed this miracle, if He had not seen that the multitude was in danger. Wherefore it goes on: And if I send them away fasting to their own houses, they will faint by the way: for divers of them came from far. The disciples did not yet understand, nor did they believe in His virtue, notwithstanding former miracles; wherefore it continues, And his disciples said unto him, From whence can a man satisfy these men with bread here in the wilderness? But the Lord Himself does not blame them, teaching us that we should not be grievously angry with ignorant men and those who do not understand, but bear with their ignorance. After this it continues, And he asked them, How many loaves have ye? and they answered, Seven. The multitudes who ate and were filled did not take with them the remains of the loaves, but the disciples took them up, as they did before the baskets. In which we learn according to the narration, that we should be content with what is sufficient, and not look for any thing beyond. The number of those who ate is put down, when it is said, And they that had eaten were about four thousand: and he sent them away; where we may see that Christ sends no one away fasting, for He wishes all to be nourished by His grace. Or by those who wait for three days, He means the baptized; for baptism is called illumination, and is performed by trine immersion. Further, the seven loaves are spiritual discourses, for seven is the number, which points out the Holy Ghost, who perfects all things; for our life is perfected in the number of seven days'd. Or there are four thousand, that is, men perfect in the four virtues; and for this reason, as being more advanced, they ate more, and left fewer fragments. For in this miracle, seven baskets full remain, but in the miracle of the five loaves, twelve, for there were five thousand men, which means men enslaved to the five senses, and for this reason they could not eat, but were satisfied with little, and many remains of the fragments were over and above.