While only the Lord can make someone “not want” (NET Bible says, “I lack nothing”), the preacher should be as prepared as he can, spiritually and vocationally, to provide the care necessary for the church so that the church does not “lack” when it comes to providing care for her members.
The image of lying down in green pastures and being led beside still waters speaks of sustenance both spiritual and physical. The shepherd was to feed the sheep and lead them into places that were not frightening (still waters were important because loud, running water would frighten the sheep so they would not drink). Likewise, the pastor who shepherds his flock must feed them with the proper food, the Word of God, and lead them, not through frightening events such as needless controversy, for example, but teach them the peace that is only in Christ and which restores the souls of those who trust in him.
The pastor must lead the sheep in paths of righteousness by teaching the truth and by modeling the truth for them. This is to be done to the glory of God, “for his name’s sake,” not so the pastor can have control or get his people to behave.
The image in v. 4 of Ps. 23, of going through “the valley of the shadow of death” and being comforted by the Lord’s rod and staff, reminds the pastor that in the difficult hours they must be especially attentive to provide the correct guidance and care. Their faithful attention during times of stress and adversity serve not only to encourage the flock, but also serve as testimony to those who witness it.