It is sometimes imagined that Jesus was nothing but sweetness and light.  But this is very wide of the mark.

As N.T. Wright (Jesus and the Victory of God, p183f) points out the Synoptic Gospels record a ‘pretty devastating catalogue of threats and warnings’.

That catalogue, as compiled by Wright, looks something like this:

Leave the dead to bury the dead (Mt. 8:22/Lk. 9:60);

Do not put the new wine into old wineskins (Mt. 9:17/Mk. 2:22/Lk. 5:37–8);

Israel is a lost sheep, without a shepherd (Mt. 9:36);

Those who do not repent will soon reach a time when it will be more tolerable for Sodom and Gomorrah than for them (Mt. 10:15/Lk. 10:12, cf. Mt. 11:20–24/Lk. 10:13–15);

Abraham, Isaac and Jacob will welcome Gentiles into the kingdom, while the sons of the kingdom will be cast out (Mt. 8:11–12/Lk. 13:28–9);

Israel must make friends quickly with her accuser, lest she be hauled off to prison (Mt. 5:25–6/Lk. 12:58–9);

Israel is like salt which has lost its savour, and is now good for nothing but to be cast out and trodden underfoot (Mt. 5:13/Mk. 9:50/Lk. 14:34–5);

Whoever denies or is ashamed of the Son of Man, of him will the Son of Man be ashamed (Mk. 8:38/Lk. 9:26);

It is better to sacrifice precious parts of the body than to go whole into Gehenna (Mt. 5:29–30/Mk. 9:43–8);

There is a narrow gate that leads to life, and there are few that find it, but the gate to destruction is broad and well-travelled (Mt. 7:13–14/Lk. 13:24);

Israel at present is like a field with wheat and weeds mixed, but there will come a day of separation and judgment (Mt. 13:24–30, 36–43);

Israel is like fish in a drag-net, good and bad together, and soon the net will be on shore and the bad fish thrown away (Mt. 13:47–50);

The master of the house will come and punish those servants who were not faithful (Mt. 24:45–51/Lk. 12:42–6);
The first will be last, and the last first (Mt. 19:30/Mk. 10:31/Lk. 13:30);

Nineveh will condemn this generation, because it repented at the preaching of Jonah, and a greater than Jonah is here (Mt. 12:39–41/Lk. 11:29–32);

This generation will be like an exorcised man reoccupied by worse demons than before (Mt. 12:43–5/Lk. 11:24–6);

Those to whom tragedies had occurred were not greater sinners than the rest; unless Israel repents, all will likewise perish, mown down by Roman guards or crushed under falling buildings (Lk. 13:1–5);

Unless the tree bears fruit this year, it will be cut down (Lk. 13:6–9);

In the messianic banquet, those who insist on the best places will be humiliated (Lk. 14:7–11);

In the coming great wedding feast, those invited were not worthy (Mt. 22:1–14/Lk. 14:15–24/Thom. 64);

Jerusalem will end up like chickens without a mother hen, unprotected in the farmyard fire (Mt. 23:37/Lk. 13:34);

The Temple has been abandoned by YHWH, and faces its fate unprotected (Mt. 23:38/Lk. 13:35);

Just as the flood swept Noah’s contemporaries away, so will this generation be destroyed (Mt. 24:37–9/Lk. 17:26–7);

Just as Lot’s wife was overtaken by sudden judgment, so will this generation be (Lk. 17:32);

There will be foolish maidens unprepared when the bridegroom comes (Mt. 25:1–13);

There will be foolish servants who hide their talent in the earth, or bury their pound in a napkin (Mt. 25:14–30/Lk. 19:11–27);

There will be unwilling subjects who will pay the price when the rightful king comes to reign (Lk. 19:14, 27);

There will be goats as well as sheep (Mt. 25:31–46);

Upon this generation will come all the righteous blood shed on earth, from Abel to Zechariah; it will all come on this generation (Mt. 23:35/Lk. 11:51);

The Temple will be destroyed, and (perhaps) rebuilt (Mk. 14:58/Mt. 26:61; cf. Mk. 13:2/Mt. 24:2/Lk. 21:6, etc.; Lk. 19:43f.; Mk. 15:29/Mt. 27:40; Thomas 71; cp. Ac. 6:14);

If they do not hear Moses and the prophets, neither will they believe even if one should rise from the dead (Lk. 16:31).