From Jesus of Nazareth vol. 2, pp. 44-5:

Here I should like to recall the advice given by Bernard of Clairvaux to his pupil Pope Eugene III on this matter. He reminds the Pope that his duty of care extends not only to Christians, but “‘You also have obligations towards unbelievers, whether Jєω, Greek, or Gentile’ (De Consideratione III/1,2). Then he immediately corrects himself and observes more accurately: ‘Granted, with regards to the Jєωs, time excuses you; for them a determined point in time has been fixed, which cannot be anticipated. The full number of the Gentiles must come in first. But what do you say about these Gentiles?… Why did it seem good to the Fathers… to suspend the word of faith while belief was obdurate? Why do we suppose the word that runs swiftly stopped short?’ (De Consideratione III/1,3).

Hildegard Brem comments on this passage as follows: ‘In the light of Romans 11:25, the Church must not concern herself with the conversion of the Jєωs, since she must wait for the time fixed for this by God, “until the full number of the Gentiles comes in” (Rom 11:25). On the contrary, the Jєωs themselves are a living homily to which the Church must draw attention, since they call to mind the Lord’s suffering (cf. Ep 363)…’ (quoted in Sämtliche Werke, ed. Winkler, I, p. 834).

The prophecy of the time of the Gentiles and the corresponding mission is a core element of Jesus’ eschatological message. The special mission to evangelize the Gentiles, which Paul received from the risen Lord, is firmly anchored in the message given by Jesus to his disciples before his Passion. The time of the Gentiles — ‘the time of the Church’ — which as we have seen is proclaimed in all the Gospels, constitutes an essential element of Jesus’ eschatological message.”