What inspire me this principle: In life as in business, people who are around us always make the difference. Indeed, being with the right people at the right time is a big part of success. As the song says, "everybody needs somebody" it's true because it is important to have partners and / or mentor to duplicate our strength to achieve our goals more easily.
As a leader, we must open our eyes to meet the right people with the same mentality and the same passions that we, to make the path together and lead the team to success.
Napoleon Hill (YouTube) about the second principle: http://bit.ly/vxDlxB