A tamed life becomes useful to God to the end.
"Now there was leaning on Jesus’ bosom one of His disciples, whom Jesus loved." -- John 13:23 [NKJV]
"As Jesus was walking along, he saw a man named Matthew sitting at his tax collector's booth. "Follow me and be my disciple," Jesus said to him. So Matthew got up and followed him." -- Matthew 9:9 [NLT] A changed heart results in a changed life.