Good question. My sense is that to get a fully satisfactory answer, Mark's version ought to be read beside the other accounts in the Synoptics (Matthew, Luke). (Those interested can read them, with the addition of John, in English and Greek at BibleGateway.)
For Mark 11:3, the parallels work this way (n.b.: although John has a version of the "Triumphal Entry" story in John 12:12-19, it does not include the details about arrangements for the donkey):
Matthew 21:3 "And if anyone says something to you, you shall say, 'The Lord has need of them,' and immediately he will send them."
Matthew 21:3 καὶ ἐάν τις ὑμῖν εἴπῃ τι, ἐρεῖτε ὅτι ὁ κύριος αὐτῶν χρείαν ἔχει· εὐθὺς δὲ ἀποστελεῖ αὐτούς.
Mark 11:3 "And if anyone says to you, 'Why are you doing this?' you say, 'The Lord has need of it'; and immediately he will send it back here."
Mark 11:3 καὶ ἐάν τις ὑμῖν εἴπῃ· τί ποιεῖτε τοῦτο; εἴπατε· ὁ κύριος αὐτοῦ χρείαν ἔχει, καὶ εὐθὺς αὐτὸν ἀποστέλλει πάλιν ὧδε.
Luke 19:31 "And if anyone asks you, 'Why are you untying it?' thus shall you speak, 'The Lord has need of it.'"
Luke 19:31 καὶ ἐάν τις ὑμᾶς ἐρωτᾷ· διὰ τί λύετε; οὕτως ἐρεῖτε· ὅτι ὁ κύριος αὐτοῦ χρείαν ἔχει.
As OP's question suggests, there are essentially three options for the referent of "the [L/l]ord" here:
- Jesus himself; or
- God; or
- someone else, with that "someone" being the owner of the animal.
The answer depends, in part, on the wider usage of ὁ κύριος (ho kurios = "the [L/l]ord") in these books, and in this context. The Synoptic gospels (Matthew // Mark // Luke) show different patterns in this regard. This is how the word "kurios" appears in the gospels:
| | with | no |
| | article | article |
| Mt | 26 | 54 |
| Mk | 6 | 12 |
| Lk | 45 | 59 |
| Jn | 16 | 36 |
It can be seen at once that Mark uses κύριος, whether with or without the article ("articular" or "anarthrous", respectively) far less often than Matthew and Luke.
Matthew appears to present the clearest case. A survey of occurrences bears out the claim of R.T. France that:1
"the Lord" as a title in this gospel elsewhere always refers to Yahweh, never to Jesus. ... The password means simple "God needs them".
In Luke, matters are less clear. ὁ κύριος is regularly used with reference to Jesus, and its precise force in Lk 19:31 is debated. I.H. Marshall notes that "The word κύριος is ambiguous", suggesting that reference to God is unlikely, the "owner" more likely, but holding open the possibility (hence the ambiguity) that hearers could understand Jesus to be, in some sense, the "owner". In view of Lk 19:33, however (a second reference to the owner), Marshall opts for the animal's owner as the most likely reference.2 Nolland, by contrast, presses the ambiguity:3
To Luke and to his readers "the Lord" here is the "Lord" of the full Christian affirmation (cf. at 7:13), though in Luke's story line, the terminology need mean no more than "the master" (of the disciples) whose authority, nonetheless, comes with his disciples, who speak the words that have been given to them by their master.
Which brings us, then, to Mark with its much smaller frequency of occurrences of the key term in question. All three possible referents have their advocates among interpreters of this gospel. The conundrum appears to be that ὁ κύριος (that is, the articular use: "the Lord") tends to be restricted, in Mark, to God: e.g. at Mark 5:19, where all are agreed it must refer to God.
Commentators seem reluctant to see this force applied in this (11:3) context, however. Gould, who is adamant that 5:19 must refer to God, takes quite a different line in 11:3, arguing that in view of its "frequent application" to Jesus, here it is simply a self-reference: Jesus is "the Master" (of the disciples who speak for him).4 Cranfield acknowledges that this is a common interpretation, but himself argues that in Mark's gospel, such a self-designation here comes too soon. He thinks reference to the owner makes more contextual sense (setting aside, then, reference to God).5
Anderson, by contrast, argues that this is precisely a unique case in Mark (thus acknowledging the common usage of ὁ κύριος), and asserts that we are
in a context in which the supreme authority of Jesus over all things is highlighted
so that for
the later Church the title 'Lord' with all that it implies is particularly appropriate.6
So, to whom does ho kurios refer in Mark 11:3? To my own mind, Cranfield and Lane make the more compelling observations, and the reference is most likely to the the animal's owner.
- the instruction (or "pass phrase") is for anyone they might encounter, and not for the animal's owner;
- Jesus' self-reference in Mark 14:14 is "the teacher"; but
- the ambiguity remains, and later readers can feel a resonance with a different "Lord" (thus the typical caplitalization in most modern English versions).
However (!), there is no knock-down argument here, and as a survey of commentators suggests, the other options have been defended by careful readers of the text.
- R.T. France, The Gospel of Matthew (NICNT; Eerdmans, 2007), p. 776.
- I.H. Marshall, The Gospel of Luke: A Commentary on the Greek Text (NIGTC; Eerdmans, 1978), p. 713.
- John Nolland, Luke 18:35-24:53 (WBC, 35C; Word, 1993), p. 925.
- E.P. Gould, A Critical and Exegetical Commentary on the Gospel According to St. Mark (ICC; T & T Clark, 1896), p. 207.
- C.E.B. Cranfield, The Gospel According to Saint Mark (CUP, 1963), pp. 349-50. W.L. Lane, The Gospel According to Mark (NICNT; Eerdmans, 1974), pp. 391-2, n. 3 adopts a similar position, adding further considerations, especially the counter-example of Mark 14:13-14, which he thinks rules out the "self-reference" option.
- H. Anderson, The Gospel of Mark (NCB; Marshall, Morgan & Scott/Eerdmans, 1976), p. 261.