From: Luke 7:18b-23
The Mission of John the Baptist
[18b] The disciples of John (the Baptist) told him of all these things.  And John, calling to him two of his disciples, sent them to the Lord, saying, "Are You He who is to come, or shall we look for another?"  And when the men had come to Him, they said, "John the Baptist has sent us to You, saying, 'Are You He who is to come, or shall we look for another?'"  In that hour He cured many of diseases and plagues and evil spirits, and on many that were blind He bestowed sight.  And He answered them, "Go and tell John what you have seen and heard: the blind receive their sight, the lame walk, lepers are cleansed, and the deaf hear, the dead are raised up, the poor have good news preached to them.  And blessed is he who takes no offense at Me."
18-23. "It was not out of ignorance that John enquired about Christ's coming in the flesh, for he had already clearly professed his belief, saying, 'I have seen and have borne witness that this is the Son of God' (John 1:34). That is why he does not ask, 'Are You He who has come?' but rather, 'Are You He who is to come?' thus asking about the future, not about the past. Nor should we think that the Baptist did not know about Christ's future passion, for it was John who said, 'Behold the Lamb of God, who takes away the sins of the world' (John 1:29), thus foretelling His future immolation, which other prophets had already foretold, particularly Isaiah (chapter 53) [...]. It can also be replied, with St. John Chrysostom, that John made this enquiry not from doubt or ignorance, but because he wished his disciples to be satisfied on this point by Christ. Therefore, Christ gave His reply to instruct these disciples, by pointing to the evidence of His miracles (verse 22)" (St. Thomas Aquinas, "Summa Theologiae", II-II, q. 2, a. 7 ad 2).
22. In His reply to these disciples of John the Baptist, Jesus points to the miracles He has worked, which show that he has investigated the Kingdom of God; He is, therefore, the promised Messiah. Along with miracles, one of the signs of the coming of the Kingdom is the preaching of salvation to the poor. On the meaning of "the poor", see the notes on Matthew 5:3; Luke 6:20 and 6:24.
Following the Lord's example, the Church has always taken special care of those in need. In our own time the Popes have stressed time and again the duties of Christians in regard to poverty caused by man's injustice to man: "Selfishness and domination are permanent temptations for men. Likewise an ever finer discernment is needed, in order to strike at the roots of newly arising situations of injustice and to establish progressively a justice which will be less and less imperfect [...]. The Church directs her attention to these new 'poor'--the handicapped, the maladjusted, the old, various groups on the fringe of society--in order to recognize them, help them, defend their place and dignity in a society hardened by competition and the attraction of success" (Paul VI, "Octogesima Adveniens", 15).
23. These words refer to the same thing Simeon prophesied about when he referred to Christ as a sign that is spoken against, a sign of contradiction (cf. Luke 2:34). People who reject our Lord, who are scandalized by Him, will not reach Heaven.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.