What does Mark 6:43 mean?
After Jesus blesses the bread and fish, He breaks the bread and gives the pieces and the fish to the Twelve to pass out to the crowd that numbers over five thousand (Mark 6:44). The Twelve had not had a real meal in some time (Mark 6:31). It's reasonable to wonder if the Twelve worry if there will be none left for them as they hand out the food to the groups of hundreds and fifties. But when the people are full, twelve real baskets full of food remain (Mark 8:19). Likely, each of the Twelve are supplied with more than what anyone else had eaten—whatever they'd already eaten plus more than enough food for each!This object lesson is one that Jesus will have to reiterate several times as He mentors the Twelve. They serve the people and are the most blessed. Whoever wants to be the greatest must be the last (Mark 9:33–35). To emulate Christ, serve first (John 13:1–17) and think of others first (Philippians 2:1–8). Those who give will be given more (Luke 6:38). If you exalt yourself, you leave no room for God to exalt you, but if you are humble God will raise your stature (Luke 14:7–11; 18:9–14).
Later, the Twelve will learn that it isn't enough to physically serve God, with rote actions. Works without faith are an attempt to win God's favor through our own merit. Hebrews 11:6 says, "And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him." At this point, the Twelve are sometimes excited that they are close intimates with the Messiah and sometimes incredibly confused (Mark 4:41). They have faith that Jesus is the Messiah, but they don't know Him or what the "Messiah" is for. They have faith to heal and expel demons (Mark 6:13), but they don't have faith to calm storms (Mark 6:45–52).
Likewise, we need to have faith in God as He is, not as we want or presume Him to be. Our understanding is seriously limited, and accepting that fact goes a long way in solidifying our faith. If we can accept that He is who He is, we can grow in our knowledge of Him. It is when we think we have Him figured out that we find His power in our lives waning.