5 And he could there do no mighty work, save that he laid his hands upon a few sick folk, and healed them.
It is important to note that when something should not be done or if it would not be appropriate to do it God has it written in a way that implies He was unable to do it. So, for the lazy Bible student this can be very confusing but it indicates a plan, forethought, and a way that God has in mind how things are to be done. See the following verses, as John Gill pointed out;
Genesis 19:22 Haste thee, escape thither; for I cannot do any thing till thou be come thither. Therefore the name of the city was called Zoar.
Jeremiah 44:22 So that the LORD could no longer bear, because of the evil of your doings, and because of the abominations which ye have committed; therefore is your land a desolation, and an astonishment, and a curse, without an inhabitant, as at this day.
God’s response is already figured out. He’s not reacting to events. He knows events beforehand and knows how He will see His will be done.
In the following verse it is not to be imagined that Joseph’s brothers were physically prevented from speaking peaceably to him but that their response to their father’s favoritism influenced their behavior.
Genesis 37:4 And when his brethren saw that their father loved him more than all his brethren, they hated him, and could not speak peaceably unto him.
See here a parallel verse to Mark 6:5;
Matthew 13:58 And he did not many mighty works there because of their unbelief.
There are times, though, when Jesus worked when the people’s faith wasn’t an issue. This is reported to prove a point to us. We complain that God isn’t doing enough for us and we don’t examine our unbelief. It is one thing to receive a negative response to our prayers because God’s will is on a different tack. It is another entirely not to receive a positive response to our prayers to God because we really don’t believe. Many Christians have more faith in their faith than they do in God. We often hear about the power of prayer when what is really only relevant is the power of the one to whom we pray.
Mark 9: 23 Jesus said unto him, If thou canst believe, all things are possible to him that believeth.24 And straightway the father of the child cried out, and said with tears, Lord, I believe; help thou mine unbelief.
Always praying in His will, according to the Bible, keeping the idea of eternity in our hearts;
1 John 5:14 ¶ And this is the confidence that we have in him, that, if we ask any thing according to his will, he heareth us: 15 And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him.
I think we can safely assume that a new Mercedes convertible if you can only afford a Nissan Centra or that your 95 year old body will start working like a 20 year old’s is not part of God’s plan. Sometimes unbelief is based on pure selfishness and unreasonable expectations. In that case God can’t help because it would go against His eternal purpose, His will for your life, or death, whatever the case may be. Does what you want line up with what God wants for you?