So almost immediately after the the violence occured, Goebbels began working overtime spreading propaganda about what had actually happened. He portrayed the SA Leader Rohm and General Kurt Von Schleicher, a former chancellor, as plotting a coup against Germany. Hitler said in a speech that

Every clenched fist that is raised against the leader and the regime, will be pried open, by force if necessary

Still he had a lot of explaining to do, as among the victims were former Nazis members like Gregor Strasser, and army majors like Ferdinand von Bredow (who Hitler thought was publishing subversive material). He said that they had all been part of Rohm's supposed coup, and they they were plotting with the French. Of course most of these people weren't in any way, shape or form plotting against Germany.

So this won the army's support as well as Hindenburg; even though the army had lost men in the purge. Von Blomberg, the Army Chief, and Hindenburg both sent congratulations and thanks to Hitler for (in the words of Hindenburg) "nipping treason in the bud". Of course by this time Hindenburg was ailing and not in his right mind.

Of course any sympathy among the general public was quickly squashed when it was revealed that Rohm had been found sleeping with a young boy when he was captured, and propaganda was spread about SA members being homosexuals and pedophiles (not unfounded, but not universally true either). Also the Nazis pushed through a law retroactively justifying the purge and legitimizing further violent purges.

Hitler gave a speech on July 13th, 1934 further justifying his actions.

If anyone reproaches me and asks why we did not call upon the regular courts for sentencing, my only answer is this: in that hour, I was responsible for the fate of the German nation and was thus the Supreme Justiciar of the German people! . . . I gave the order to shoot those parties mainly responsible for this treason . . . The nation should know that no one can threaten its existence - which is guaranteed by inner law and order - and escape unpunished! And every person should know for all time that if he raises his hand to strike out at the State, certain death will be his lot.

Hitler's fiery rhetoric ensured that there would be no vocal criticism from either the Reichstag or the German Judiciary; less they be branded communist sympathizers.

Social Democratic Agents, loyalty to the former social democratic party, who's leadership had either fled or been imprisoned, reported that the Nazis were arresting anyone caught questioning the purge and sending them to concentration camps. But they also reported that many people seem relived to no longer have the SA stormtroopers patrolling the streets.

In private Von Blomberg assured Hitler that the army was now completely devoted to him, and he was grateful that the army no longer had to fear a take over by the SA. A young Claus Von Stauffenberg, who in ten years would try and kill Hitler, described the action as "Lancing a troublesome boil", he confided to one of his army friends that he could have been there to see Rohm die.

So outside of the usual gossip and story swapping, staunch criticism of the action had to come from outside Nazi Germany. Kaiser Wilhelm II said two things on the matter:

"What would people have said if I had done such a thing?

And upon hearing of the murder of Kurt Von Schlicher's wife:

We have ceased to live under the rule of law and everyone must be prepared for the possibility that the Nazis will push their way in and put them up against the wall!

For the exiled Social Democrats and Communists it was just another instance of violence from a regime that had already committed great acts of violence, so it served to further reinforce there hatred of the Nazis. But by that point there was very little they could do besides, Hitler was far too popular and too well entrenched in power for their pleas to have any affect.