On February 18, 1855 Wilford Woodruff attended a meeting where Brigham Young spoke. He then went to another ward to speak and said, 

“I have been full of thought and reflection this day while sitting and hearing from President Young. I feel to thank God with all my heart that He has bestowed upon us such a leader in this dispensation. Yes, President Young is a leader in Israel and one that is not ashamed to rebuke sin in high places. He guards well the interest and salvation of this people regardless of all consequences. I feel it my duty as an Apostle of Jesus Christ and an Elder in Israel to sustain him in his office & back up his testimony by my faith and works. I also consider it the duty of every apostle, bishop, elder, officer, and member in the Church of Jesus Christ to do the same. If we are not willing to do it we are not worthy of the place we occupy.”

Wilford Woodruff sustained Brigham Young as prophet and showed that by his faith and works. 

How do you sustain our current prophet, President Nelson?