Ok, I'm not a Trump supporter, but if you look at what Trump said, he was talking about Hillary's
deleted emails.
You know, the ones that were deleted years ago.
He was not asking Russia to hack anything, he was asking that if the Russians had already got access to those emails (due to their own hacking) then they should provide them to the FBI. It's a subtle but important difference.
It's also worth noting that this is well within the scope of a treaty [0] between the US and Russia (signed by none other than Bill Clinton) covering mutual legal assistance in criminal matters (which this surely is).
If you believe that Trump is encouraging Russia to hack various people in order to influence the US election, you have probably been deliberately misled by various media outlets.
I say deliberately because if you look at the media outlets driving this story, it's the same ones the DNCleaks show are in direct collusion with the DNC. The DNCleaks also contain information on a strategy that the DNC would try to distract the public from Hillary's email scandal if anything was released from that by trying to put the blame on Russia trying to influence the election (playing to the general public's confirmation bias that Trump and Putin are buddy-buddy).
The thing is though, that if there was enough evidence of wrongdoing in those deleted emails that they could influence the outcome of the US election, then Hillary Clinton probably shouldn't be running for president in the first place.
Here's a thought experiment:
Imagine if the deleted emails contain incriminating content that would cause Hillary to lose the election.
Imagine Russia hacked Hillary's server and got access to them.
Imagine if they don't release them.
Imagine if Hillary becomes president.
Congratulations, now Russia has something they can use to blackmail the president of the United States.
Either there's nothing of importance in the emails and Russia providing them (assuming they even had them) would have no influence on the election, or there is something of importance in them and that disqualifies Hillary as a suitable candidate.
Either way, none of that is on Trump.
0: https://www.congress.gov/treaty-document/106th-congress/22