An expression of confidence in God's protection (a song of trust). The LORD is compared to a shepherd. Soul means vitality, life. Path of righteousness, or "of rightness," that is, right paths which suits the context better. Shadow of death is the reading of the scribes, but "deep darkness" is the better rendering; where the same Hebrew expression occurs. The LORD is compared to a gracious host. Dwell in house of the LORD means to worship in the temple. For ever, Hebrew "for length of days," meaning as long as I live.
Jesus is the Good Shepherd. At night, sheep were often gathered into a sheepfold to protect them from thieves, weather, or wild animals. The sheepfolds were caves, sheds, or open areas surrounded by walls made of stones or branches. The sheepfold often slept in the fold to protect the sheep. Just as a shepherd cares for his sheep, Jesus the Good Shepherd, cares for his flock (those who follow him). The prophet Ezekiel, in predicting the coming of the Messiah, called him a Shepherd (Ezekiel 34:23).
The life that Jesus gives is abundantly richer & fuller. It is eternal, yet is begins immediately. Life in him is lived on a higher plain because of his overflowing forgiveness, love, & guidance.
A hired man tends the sheep for money, while the shepherd does it for love. The shepherd owns the sheep & is committed to them. Jesus is not merely doing a job, he is committed to love us & even lay down his life for us. False teachers & false prophets do not have this commitment.
The "other sheep" were non-Jews. Jesus came to save Gentiles as well as Jews. This is an insight into his worldwide mission-to die for the sins of the whole world.
Reference summary used from The New Oxford Annotated Bible with The Apocrypha Expanded Edition RSV & The Life Application Bible KJV, Tyndale House Publishers, Inc., Wheaton, IL