Why did Jesus arrange his 11 disciples in two places on the way to his place of prayer in Gethsemane?

Question

We read in Matt 26:36-39 (NRSVCE) :

Then Jesus went with them to a place called Gethsemane; and he said to his disciples, “Sit here while I go over there and pray.” He took with him Peter and the two sons of Zebedee, and began to be grieved and agitated. Then he said to them, “I am deeply grieved, even to death; remain here, and stay awake with me.” And going a little farther, he threw himself on the ground and prayed...

One wonders why Jesus asked his 11 disciples to remain in two different places on his way to the place of prayer in Gethsemane And Peter was carrying a sword ! ( Jn 18:10). Did Jesus anticipate an early arrival of his betrayer and the soldiers, who needed to be warded off till he completed his prayer? Was the arrangement of disciples in two steps i.e. 8 plus 3, intended to reinforce physical security in all his human nature?

My question, therefore is: According to Catholic teachings, why did Jesus arrange his 11 disciples in two places on the way to his place of prayer in Gethsemane?

Answer 1

It wasn't only in the garden that Jesus delineated two groups of apostles.

And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart, Mt 17:1

And he suffered no man to follow him, save Peter, and James, and John the brother of James. Mk 5:37

And it came to pass about an eight days after these sayings, he took Peter and John and James, and went up into a mountain to pray. Lk 9:28

So, why did this happen? Why was there an apparent inner circle of three among the twelve?

For the Catholic Church, Peter and successors is their visible foundation. This separation is fairly easy to understand.

936 The Lord made St. Peter the visible foundation of his Church. He entrusted the keys of the Church to him. The bishop of the Church of Rome, successor to St. Peter, is "head of the college of bishops, the Vicar of Christ and Pastor of the universal Church on earth" (CIC, can. 331). -CCC-

But what of James and John?

One reason was the adage that by the mouth of two or three witnesses will something be established (Mt 18:16, Deut 17:6).

Jesus' Transfiguration takes place on a high mountain, before three witnesses chosen by himself: Peter, James and John. -CCC-

So, this might explain the necessity of an "inner group", but except for Peter's explanation as head, why James and John?

There may be a hint of an explanation here. Jesus foreknew His future and established the care for His mother. James and John sons of Zebedee and Salome who was the sister of Mary were cousins.

If this last supposition is right, Salome was a sister of the Blessed Virgin Mary, and James the Greater and John were first cousins of the Lord; this may explain the discipleship of the two brothers, Salome's request and their own claim to the first position in His kingdom, and His commendation of the Blessed Virgin to her own nephew. But it is doubtful whether the Greek admits of this construction without the addition or the omission of kai (and). Thus the relationship of St. James to Jesus remains doubtful. NewAdvent

James and John were also the first and last apostles to die.

So, from a Catholic point of view, there were three witnesses to prove, one who was the visible foundation of the subsequent Church and two who were most likely cousins to care for Mary.

Answer 2

St. Thomas writes (Commentary on Matthew 26:36):

Damascene raises a question. Prayer is the ascent to God, but Christ’s intellect was joined to God, why, therefore, did God who was doing this need to do this?
[…]
He, therefore, gives an example of praying, and how one ought to pray. For the first condition of prayer is that

1. prayer ought to be humble: which is signified because He went to a valley; “The prayer of the humble and the meek hath always pleased thee” (Jud. 9:16).
2. Likewise, prayer ought to be devout; hence, He prayed in Gethsemani, namely, in a garden of fatness; “Let my soul be filled as with marrow and fatness” (Ps. 62:6).
3. Similarly, it ought to be solitary, as it was said above: “Enter into thy chamber, and having shut the door, pray to thy Father” (Mt. 6:6).