When our bees produce honey within the hives' frames, they seal the honey with a thin layer of wax so it stays within the honeycomb. As we extract the honey from the frames, we need to scrape off that wax seal so that the honey can run out as we spin it. This is the wax that we gather and melt into little blocks so it can be used to make candles, wraps, lip balms and many other things!
As all raw honey will crystallise at some point this will happen to your honey, too. To liquify your honey again you simply need to warm up the jars again. Try not to heat it much over 40 degrees celsius so that the honey will remain "RAW HONEY". This can be done in the sun outside on a warm day, in a water bath, microwave or a low set oven.
It will just take some time for the heat to get through the entire jar.