All the blessings, assurances, and comfort which God gives to a believer flow from the blessed truth in the first verse of Psalm 23.
Needs Supplied (vs 1-2)
Because a believer can say, "The Lord is my Shepherd," he is assured that he will not want. The Lord, in His love, compassion, and power will supply all the spiritual and temporal needs of believers. He is Jehovah-Rohi (The Lord my Shepherd), and He is Jehovah-Jireh (The Lord will provide, Genesis 22:14). The relationship between the Lord and a believer is close, tender, and eternal. The Lord knows every detail of our spiritual, mental, and physical conditions (Psalm 139:1-6; John 10:14, 27), and loves each one of us with a divine, sacrificial love (Galatians 2:20).
Psalm 23 has been a source of blessing to generations of believers. David, the Shepherd King of Israel (2 Samuel 7:8; Psalm 78:70-72), wrote the Psalm, being led and directed by the Holy Spirit (1 Peter 1:21). David knew that sheep need to be cared for, provided with good pasture and with clean water. He knew that sheep wander and have to be searched for and brought back to the flock. David knew that sheep need guidance and protection against disease and predators (1 Samuel 17:34-36).
The Lord was moved with love and compassion when He saw multitudes of people waiting to listen to Him. Their leaders were not meeting their spiritual needs, they were not leading, teaching, and protecting them. The people were "as sheep not having a shepherd" (Mark 6:34). The Lord, the Shepherd of the sheep, provides spiritual food as well as food to meet the needs of our bodies (James 1:17). He gives us His written Word on which to feed and meditate (1 Peter 2:2; Psalm 119:105). The Holy Spirit, Who dwells within us, will teach us, and if we are obedient to the truths He reveals, will empower us to obey the will of God. This will produce in us a peace that "passeth all understanding" (Philippians 4:7). Sheep with good pasture, and who are feeling safe, will lie down peacefully without fear.
Restoration & Comfort (vs 3-5)
If the believer does not respond to His written Word, God may need to chastise him further. The Lord restores the believer to Himself, so that He might lead him "in the paths of righteousness." The Lord does all this for the believers blessing and "for His names sake," that is, for His own honor and glory.
In the first three verses of the Psalm, the Psalmist speaks about the Shepherd. In verses 4 and 5 he speaks to the Shepherd. Problems come to believers and we may have to pass through "the valley of the shadow of death" before the Lord returns. The Lord is always with a believer and He will be with us when we pass through death. Trials and death are real, but for the believer, there is light beyond. The Lord, who is Jehovah Shammah (The Lord is there, Ezekiel 48:35) will be with the believer in life, in death, and eternally in heaven (2 Corinthians 5:8), where there is "fulness of joy" and eternal pleasures. For the believer, "to die is gain" (Philippians 1:21).
The believer can say, "I will fear no evil: for Thou art with me." In verse 4 the Shepherd is seen with a rod, for the protection, control, and correction of the sheep, and a staff for the care of the sheep, to draw it to Himself and to the other sheep.
The Sovereign Lord, Who is our Shepherd, provides all our blessings in the midst of this evil world in which we are strangers and pilgrims. He provides us with all that is necessary for our spiritual blessing in the presence of our "enemies," the world (John 15:18,19), the flesh (Galatians 5:17), and the devil (1 Peter 5:8). Victory over our spiritual foes is assured only if, in that battle, we stay close to the Lord, Who is Jehovah-Nissi (The Lord is my banner, Exodus 17:15).
The Psalmist wrote, "Thou anointest my head with oil." Oil speaks of the Holy Spirit, Who will teach us from the Word of God. If we obey His teaching, our lives will be lived in accordance with the will of God and to His glory. Where His Word is obeyed in assemblies of Gods people, love among believers will be evident, there will be unity, and blessing will surely follow (Psalm 133:1-3). The Lord will shower blessings on the obedient believer, and he will be able to say, "My cup runneth over." The blessings he receives will result in blessings for those with whom he comes into contact.
Blessings Now & Eternally (v 6)
In the last verse of Psalm 23, the Psalmist speaks about the blessings the Shepherd bestows upon the believer, both in this life and in eternity. The Shepherd is Jehovah-Mekadeshcem (The Lord that doth sanctify, Exodus 31:13), and He wants to lead us on into greater practical sanctification. The Lord is seeking to lead us to greater spiritual maturity that, by grace, we may be conformed more and more to the image of the Lord Jesus Christ.
It has often been said that Psalm 23 reveals the source, for the believer, of a happy life, a happy death, and a happy eternity. The source is the Shepherd, the Lord Jesus Christ. Going before us is our omnipotent Shepherd. We are protected on every side (Psalm 34:7). Underneath are the "everlasting arms" (Deuteronomy 33:27), His banner over us is love (Song of Solomon 2:4), and following us are "goodness and mercy."
The Lord, in His goodness, supplies all our needs; in His mercy and grace, He forgives all our sins; and He will never forsake us. He gives us eternal life, and we "will dwell in the house of the Lord for ever."
Pastures abundant doth His hand provide,
Still waters flowing ever at my side.
Goodness and mercy follow on my track,
With such a Shepherd, nothing can I lack.
- M. E. Upham