2 Nephi 4:16

"Behold, my soul delighteth in the things of the Lord; and my heart pondereth continually upon the things which I have seen and heard."

Nephi continually pondered spiritual matters, and I am sure this is why he was so close to the Spirit and had so much power. I'm sure since he thought about the gospel often that it was easier for him to choose the right and follow God's plan. It was probably easier for him to resist temptation and do good things. I need to ponder more on spiritual things.