Objection 1. It would seem that Christ should have preached to the Jews without offending them. For, as Augustine says (De Agone Christ. xi): "In the Man Jesus Christ, a model of life is given us by the Son of God." But we should avoid offending not only the faithful, but even unbelievers, according to 1 Corinthians 10:32: "Be without offense to the Jews, and to the Gentiles, and to the Church of God." Therefore it seems that, in His teaching, Christ should also have avoided giving offense to the Jews.
Objection 2. Further, no wise man should do anything that will hinder the result of his labor. Now through the disturbance which His teaching occasioned among the Jews, it was deprived of its results; for it is written (Luke 11:53-54) that when our Lord reproved the Pharisees and Scribes, they "began vehemently to urge Him, end to oppress His mouth about many things; lying in wait for Him, and seeking to catch something from His mouth, that they might accuse Him." It seems therefore unfitting that He should have given them offense by His teaching.
Objection 3. Further, the Apostle says (1 Timothy 5:1): "An ancient man rebuke not; but entreat him as a father." But the priests and princes of the Jews were the elders of that people. Therefore it seems that they should not have been rebuked with severity.
On the contrary, It was foretold (Isaiah 8:14) that Christ would be "for a stone of stumbling and for a rock of offense to the two houses of Israel."
I answer that, The salvation of the multitude is to be preferred to the peace of any individuals whatsoever. Consequently, when certain ones, by their perverseness, hinder the salvation of the multitude, the preacher and the teacher should not fear to offend those men, in order that he may insure the salvation of the multitude. Now the Scribes and Pharisees and the princes of the Jews were by their malice a considerable hindrance to the salvation of the people, both because they opposed themselves to Christ's doctrine, which was the only way to salvation, and because their evil ways corrupted the morals of the people. For which reason our Lord, undeterred by their taking offense, publicly taught the truth which they hated, and condemned their vices. Hence we read (Matthew 15:12,14) that when the disciples of our Lord said: "Dost Thou know that the Pharisees, when they heard this word, were scandalized?" He answered: "Let them alone: they are blind and leaders of the blind; and if the blind lead the blind, both fall into the pit."
Reply to Objection 1. A man ought so to avoid giving offense, as neither by wrong deed or word to be the occasion of anyone's downfall. "But if scandal arise from truth, the scandal should be borne rather than the truth be set aside," as Gregory says (Hom. vii in Ezech.).
Reply to Objection 2. By publicly reproving the Scribes and Pharisees, Christ promoted rather than hindered the effect of His teaching. Because when the people came to know the vices of those men, they were less inclined to be prejudiced against Christ by hearing what was said of Him by the Scribes and Pharisees, who were ever withstanding His doctrine.
Reply to Objection 3. This saying of the Apostle is to be understood of those elders whose years are reckoned not only in age and authority, but also in probity; according to Numbers 11:16: "Gather unto Me seventy men of the ancients of Israel, whom thou knowest to be ancients... of the people." But if by sinning openly they turn the authority of their years into an instrument of wickedness, they should be rebuked openly and severely, as also Daniel says (Daniel 13:52): "O thou that art grown old in evil days," etc.
Source: Summa Theologica (New Advent)