Ok when you have the samsung keyboard open, press the gear icon button thingy.
That will bring you to settings > samsung keyboard settings.
Scroll all the way down to "Reset settings" and press that.
Then scroll back up to the select input languages, press that and it'll have a popup and that'll ask you if you want to download new langs now, do that.
Scroll down and you'll see one like עִבְרִית, select that and it'll download that and then you can select the downloaded langs on the top of that screen.
And then it'll work when you swipe the space bar.
My region is ttt, I'm not sure what your phone's is.
You phone's rom region may not have that selection anymore ^^, just something to keep in mind.
If this doesn't work after a fresh rom install or something then I would go find a diff region to flash.
I'm not even sure how to change the csc anymore though on 4.4.2, my script doesn't work anymore for that and most of the phone codes don't work either so I can't check it.
I kinda suspect the nb3 rom, ttt region isn't actually ttt but whatever lol.
I'm pretty sure it doesn't matter though.
The link one-option posted above is where I get my roms from and so does most everyone else that does manual updates.
What does עִבְרִית mean anyways?