We must set our heart to obey God's will for our lives to avoid the kind of mistakes these men below made. We need to be committed to setting aside our own desires in favor of God's will. In other words, we must value the eternal over the temporal and be satisfied with what the Lord has planned.
Esau sold his future for a bowl of stew. His blindness to what was truly valuable caused him to lose his inheritance. There are other people who can teach us additional lessons about protecting our future.
David was chosen by God to lead the nation, and for many years, he pursued the Lord's plan. However, his desire for Bathsheba led him to commit adultery and arrange for her husband to die. Because he chose to gratify his own wishes instead of following God's ways, he fell into sin. When confronted by the prophet Nathan, David sincerely repented (2 Sam. 12:7, 13), but he and his family were deeply affected by his mistake.
Samson was another one who knew what the Lord required but disobeyed--like David, he gave up blessings for temporal pleasure. Losing sight of God's purpose for him, Samson chose instead to please his untrustworthy companion, Delilah (Judg. 16:15-17). As a result, he spend his last years in disgrace.
A final example is Judas Iscariot, who wanted Jesus to establish the kingdom of God immediately. Because he valued earthly matters above spiritual ones, he rejected Jesus' teachings and tried to manipulate events to his own liking. He was convinced he knew what was right.