The transition from tending flocks to leading an entire nation is not a matter of chance. The practical and moral education a shepherd receives in the fields provides the exact qualities God seeks in a leader. Caring for helpless animals, especially the youngest and most vulnerable, requires constant supervision and profound gentleness. The primary approach among commentators is that this applies specifically to nursing sheep raising their young, which demand an exceptionally careful touch [רד״ק, מצודת ציון, מאירי, אבן עזרא, ביאור שטיינזלץ]. A truly skilled shepherd walks behind these nursing mothers, ensuring they are never rushed and guiding them at a slow, safe pace [רד״ק, מאירי, מצודת דוד].
This careful management of the flock served as a deep test of compassion. While tending his father's sheep, he displayed extraordinary mercy by tailoring the food to the specific abilities of each animal. He would first lead the tender young kids to eat the soft, upper blades of grass. Next, he allowed the older goats to eat the middle sections of the plants. Finally, he brought in the older, stronger sheep, who were capable of chewing the tough, deep roots. Observing this deep empathy and individualized care, God determined that a person who shows such profound mercy to animals is the ideal candidate to shepherd the Israelites [רש״י].
Brought directly from following the nursing sheep, he was transformed from a caretaker of animals into the king and shepherd of a nation [אבן עזרא, מצודת דוד]. God knew that he alone was truly fitting for this immense responsibility [אלשיך].
His leadership is divided into two distinct aspects: guiding the people of Jacob and tending to the inheritance of Israel. This division is not merely poetic. The concept of an inheritance points to a deeper layer of holiness and faith that uniquely characterizes the nation [מלבי״ם]. Additionally, this dual role introduces a dimension of time. Guiding the people relates to his immediate, present reign, while tending to the inheritance suggests a lasting legacy, hinting that his leadership will continue to endure far into the future, extending even into the days of the Messiah [אלשיך].