The disciples were in Galilee. They had just been participants in Christ’s miracle of feeding the 5000+ with two fish and 5 loaves of bread. Right there Christ suspended the laws of nature to do so.–Especially when you recall that they had more leftovers than they began with! Now Jesus is tired, after all He is True Man as well as being True God. So, He goes off by Himself to pray. Meanwhile the disciples get into a boat and journey to the far shore—about 20 odd miles away—to await Him joining them. The boat was well away from shore toward the middle of the lake when a furious sudden squall comes up. They row and row but the boat is taking on water and they are afraid of drowning. Around 4 a.m. Jesus sees all this from His vantage point and decides to help them. So, He literally “walks on the water” until He gets close. Did He suspend the law of gravity? Or, is He above that law so as to not be affected by it? In any case, they are terrified because they thought He was a ghost! I find all this mystifying in that they had just been His hands in a huge miracle a few hours before, but now they apparently forgot its truth which is: Jesus always takes care of His children.