Robert M. Grant and David Noel Freedman write: “Just as in the synoptic gospels (Matthew 21:42; Mark 12:10; Luke 20:17), the saying about the stone which the builders rejected is appended to the parable of the vineyard. (The Naassenes too were impressed by this mysterious saying; cf., Hippolytus, Ref., 5, 7, 35.) But Thomas deletes the synoptic reference to ‘reading’ this saying (Matthew, Mark) or to the fact that it is ‘written’ (Luke) – actually in Psalm 118 (117):22-23 – because he is avoiding mention of the Old Testament. See Sayings 53 and 66 and Commentaries.” 

F. F. Bruce writes: “In all three Synoptic Gospels the parable of the vineyard is followed by the quotation of Psalm 118.22: ‘The stone which the builders rejected has become the head of the corner’ (i.e. top of the pediment). The point is that Christ, rejected by the leaders of Israel, is exalted by God (cf. Acts 4.11). Here no reference is made to its being an Old Testament quotation. Hippolytus tells us that the Naassenes spoke of the archetypal heavenly Man (whom they called Adamas) as ‘the chief corner stone’. [Refutation v.7.35.]” 

Funk and Hoover write: “The fact that the allusion to Ps 118:22 follows on the parable of the leased vineyard in Thomas as it does in the synoptics, even though Thomas lacks the allegorical overlay of the synoptic edition, indicates that the connection may have been the first step in reading the parable as an allegory, since the rejected stone was probably understood to refer to Jesus in Christian circles: the rejected stone that has become the keystone stands for the rejected Jesus, who has become the centrepiece of the new movement.” 

Gerd Ludemann writes: “This piece also appears in Mark 12.10-11 par. and fits in well there, because the verses give the reason for the rejection of Israel. But as they do not fit with Thomas here, it follows that they have been taken over, together with Mark 12.1-9, from the Synoptics.”