Lack of Gratitude

• In the latter half of 1 Nephi 17 all Nephi's brothers do is complain and desire to destroy Nephi's life bc of the trials they've had to endure in the wilderness.  In vs. 41-44 Nephi tells of the many blessings and mercies the Lord has placed on their people. In the next verses 45-48 Nephi speaks with such power (he is a little bit angry at this point) as he calls them to repentance asking how could they NOT believe anything is possible with God when they've been witnesses to so many miracles. Even as I read this, I can feel how urgent Nephi is in trying to convince his brethren. 
• In 17:53, the Lord sees fit to give Nephi's brethren yet another sign to show them that the Lord is able to help them accomplish what needs to be done.  So now they have seen an angel, heard the Lord's voice as a whisper and as thunder, felt the Spirit of the Lord in Nephi as he speaks to them AND now he shocks them with Nephi's touch.  How much will the Lord have to show the unbelievers until they finally have a strong enough testimony that it will stick?