Peter Pett's Commentary on the Bible
Luke 17:5,6
‘And the apostles said to the Lord, “Increase our faith.”
And the Lord said, “If you had faith as a grain of mustard seed,”
You would say to this sycamine (mulberry) tree, ‘Be you rooted up, and be you planted in the sea,'
And it would obey you.”
The plea for increased faith is by ‘the Apostles' in contrast with ‘the disciples' in Luke 17:1. The Apostles are growing in their awareness of the importance of their position, and of their own weakness for the task. They feel therefore that they need their faith to be made stronger. But Jesus, who sees much further ahead, wishes to bring home to them that it is not the strength of their faith that matters. What matters is the One in Whom they have faith. If their faith is in the right Person, and they see Him for what He is and recognise their own position within His purposes, then even the tiniest faith will accomplish mighty things. But in order for this to be so they must be people of a forgiving spirit. We should note in this regard that in the passage in Mark which deals with a similar subject exercising faith and forgiveness are closely connected (Mark 11:23).
Their appeal for increased faith arouses in Jesus a desire to prepare them for the future that lies ahead. For He knows that they will not always just be ministering among a small group of spiritual ‘babes in Jesus' in Palestine who need to be tended, and guided over obstacles (Luke 17:1), and forgiven when they fail (Luke 17:3). They will shortly be facing the greater task of going out to the world with the Good News of the Kingly Rule of God.
This sudden introduction of words which transcend their context has been noted earlier, compare Luke 10:17; Luke 12:49. We have another example here.
So now is the time for them to stop looking at their own faith and to recognise that they serve the One Who can do great things, and because He has chosen them, will do even greater things through them. For as they serve God in obedience to His commands even the tiniest of faith will accomplish the impossible. If they have faith as small as a mustard seed they will be able to command a ‘sycamine tree' to be rooted up and replant itself (phuteuo) in the sea.
At a minimum this is telling the Apostles that in the future they are going to do wonderful things. There would be no point in it otherwise. And aware of this he is concerned that they do not as a result become proud and arrogant. That is why He follows up this statement with a parable on humbleness of service. But there is probably more to it than that as we now see.
For in the Old Testament the replanting of a tree is regularly symbolic of the establishment of a nation (see Psalms 80:8 (kataphuteuo); Psalms 80:15 (phuteuo); Isaiah 5:2 (phuteuo); Jeremiah 2:21 (phuteuo); Ezekiel 17:3 (phutos), Ezekiel 17:22 (kataphuteuo); Luke 19:10 (phuteuo)).
The sycamine, probably the black mulberry tree, was a large tree, common in the Shephelah, with very strong and enduring roots, and that had a very long life. It was the equivalent in Palestine to the cedar in Lebanon, and the oak in Bashan. It was seen as immovable and almost indestructible. Moreover the coming Kingly Rule of God has been likened to a similar mighty tree in Ezekiel 17:22 (in that case a cedar). Furthermore the Kingly Rule of God has already been likened in Luke to a mustard tree which grew large from a mustard seed (Luke 13:19), while Israel is likened elsewhere to the vine, the olive tree and the fig tree when fruitfulness is in mind. So a mulberry tree (sycamine) would be a suitable picture of the strong, expanding and firmly rooted Kingly Rule of God, for it was a common tree in Palestine and often spoken of alongside the olive and the vine, and seen as the recognised Palestinian equivalent of the cedar, even if a little inferior to it (1 Kings 10:27; 1 Chronicles 27:28; 2Ch 1:15; 2 Chronicles 9:27; Psalms 78:47; Isaiah 9:10 in LXX). Being ‘planted in the sea' could represent being established among the tumult of the nations. For the sea is regularly seen as representing the nations. See Psalms 65:7; Isaiah 17:12; Daniel 7:2; Revelation 13:1; compare Isaiah 57:20. Thus the thought here may be either of transplanting the new Israel and setting it among the nations, or of transplanting the Kingly Rule of God from its beginnings in Palestine and setting it among the nations. In the context of ‘faith like a grain of mustard seed', which has previously been linked with the growth of a tree representing the Kingly Rule of God (Luke 13:19), the thought of the transplanting of a strong and powerful and enduring tree may well be an expansion on that idea.
Here then the mulberry tree may be seen as representing the Kingly Rule of God, as the vine and the fig tree can also do (John 15:1), the mulberry tree being cited here because of its being a symbol of strength and permanence (when the vine and fig tree are called on it is to illustrate fruitbearing, not permanence). The idea is thus that just as they are to nurture the infant new Israel by preventing stumblingblocks (Luke 17:1) and by a constantly forgiving relationship towards those who are genuine believers and repent of sin daily (Luke 17:3), so they will also establish the mulberry tree of the Kingly Rule of God among the tumult of the nations. And He wants them to know that they do not require increased faith for this purpose, just confidence in a mighty God. Compare here Acts 4:24. It is a declaration that the faith that they already have is sufficient for the task in hand.
This rooting up and replanting of the Kingly Rule of God is clearly depicted in Acts where Jerusalem is finally rejected and replaced as the source of the proclamation of the Kingly Rule of God by Syrian Antioch (Acts 12-13; Acts 21 - see our commentary on Acts).
Note On How This Contrasts With Mark 11:20.
In Mark 11:20 we have a passage with a similar emphasis on what a little faith can do, but there the picture is of the ‘casting' of a mountain into the sea, rather than that of ‘replanting' a tree there. In the context of the cursing of the fig tree, which represents God's curse on Jerusalem for rejecting the Kingly Rule of God, the disciples are told there that by their faith they will be able to cast a mountain into the sea. In context the mountain is the Temple mount. The casting of it into the sea thus refers to its being subjected to the tumult of the nations as a result of its resistance to the establishment of the Kingly Rule of God as revealed in its behaviour towards Jesus and its persecution of His followers. We can compare here what He would say shortly concerning the destruction of Jerusalem (Mark 13; Luke 21:20). It is the negative side of what in this statement in Luke is the positive side.
End of note.