John 21:1-5

"After these things Jesus manifested Himself again to the disciples at the sea of Tiberias; and He manifested Himself in this way.  There were together Simon Peter, and Thomas called Didymus, and Nathanael of Cana of Galilee, and the sons of Zebedee, and two other of His disciples.  Simon Peter said to them, 'I am going fishing.'  They said to him, 'We will come with you.'  They went out, and got into the boat; and that night they caught nothing.
But when the day was now breaking, Jesus stood on the beach; yet the disciples did not know that it was Jesus.  Jesus therefore said to them, 'Children, you do not have any fish, do you?'  They answered Him, 'No.' "

Amazing days, those that followed the resurrection of our Lord Jesus, when He taught needed lessons that (1) He is sovereign; (2) He is sufficient; and (3) He is to be taken seriously.

(1) He communicated His sovereignty in the very revealing of Himself to selected followers.  As Chrysostom put it, "His body after the resurrection was only visible by a distinct act of His will.  From that time the disciples did not, as before, see Jesus, but He appeared unto them.  It is not for nothing that the language is changed.  Henceforth, He was to be recognized not by the flesh, but by the spirit; not by human faculties, but by Divine perceptions: His disciples were to walk by faith, and not by sight."
This is reminiscent of Mary's encounter at the tomb... "...she turned around, and beheld Jesus standing there, and did not know that it was Jesus," (John 20:14).  In speaking her name, the Lord simultaneously opened her spiritual eyes to recognize Him.  
On a similar occasion, seven miles from Jerusalem, the Lord Jesus approached two disciples on the road to Emmaus, as they discussed the recent happenings in Jerusalem.  As Luke records it (Luke 24), "their eyes were prevented from recognizing Him," (v. 16).  In the process of breaking bread with them, "...their eyes were opened and they recognized Him..." As sovereign Lord of life and death, He decided when they would be able to grasp Who He was, and the nature of His glorified body (at that moment "He vanished from their sight").  
Note, too, that He did not manifest Himself indiscriminately.  He did not go back to Pilate, for instance, show him His wounds and declare, "THIS is truth."  He didn't go to the emperor in Rome to declare His rightful reign and rule over all.  No, in absolute sync with His Father's sovereign will, He appeared only to His own, at times most fitting, and in a manner having the greatest impact. 

(2) In revealing Himself on multiple occasions following His resurrection, He assured & reminded His followers that He was, is, and ever will be sufficient.  He had protected, provided for, and shielded His apostles for some three years... all the while predicting His leaving (such as the lengthy discourse in the upper room [John 14]), accompanied by promises of provision.  Yet His death was so devastating, followed by three days and three nights of seeming abandonment, that His men were on the brink of total despair and resignation.  Apparently, Peter's solution was to return to his prior livelihood (v.3).  If Jesus wasn't going to provide as before, maybe it was time to get back to what he knew best: fishing.  The others didn't have a better plan, so they decided to go, as well.  
In these verses, through verse 14, the Lord demonstrates vividly that He will never leave nor forsake them (or us).  First, He appears to them, which was a gracious condescension to their need to see Him, physically.  Secondly, He causes them to recognize that it is Him (v. 7).  Thirdly, He produces a substantial breakfast (v. 9), which He apparently created, as He had done for the multitudes (John 6:1-13).  Throughout this scenario, the Lord Jesus is demonstrating His sufficiency, encouraging them to believe Him for their future needs.
  
(3) There is within our passage also a needed word of warning... an ongoing caution to take our Lord and His calling seriously.  
These were skilled and experienced fishermen, who knew that nighttime was best for fishing on this lake (cf. Luke 5:5)...yet, despite all their "tricks of the trade" they caught nothing.  This was a lesson from the Lord, that there was to be no going back from their call nor their commitment (Matthew 4:19,20).  As John MacArthur observes, "they had failed to reckon sufficiently with Jesus' plan for their lives, and His ability to supernaturally hinder their efforts.  It is as if He said, 'Do anything else, and I will see to it that you fail!' "
  
Oh, that we would increase in sensitivity, becoming "the mature, who because of practice have their senses trained to discern good and evil," (Hebrews 5:14).  The previous verse gives the key to how this is accomplished: we must become "accustomed to the word of righteousness."  As our minds, hearts, and spirits are soaked in the Truth of Scripture's righteousness, we will mature in understanding the Spirit's urgings and impedings.