Bringing life into the world and continuing a family line goes far beyond human effort or the natural order. While a person might work tirelessly to gather wealth and build a legacy for the future, they often forget that the very existence of heirs rests entirely in the hands of God. He alone holds the keys to fertility, granting the gift of life to whomever He chooses [אבן עזרא, מצודת דוד]. True success and reward for a righteous person are not measured by material riches, but rather by the blessing of offspring [אלשיך, מאירי]. This profound gift is the finest and most excellent heritage a person could ever hope to receive [מאירי].
Historically, this realization brought deep comfort to King David. After learning that he would not be the one to build the Temple, but that his son Solomon would complete the task, David recognized that the greatest good God can give a person in this world is their children [רד״ק, מאירי].
Receiving this blessing requires a person to direct their prayers to the One to whom all children ultimately belong. Furthermore, it is granted as a reward to those who conduct themselves with holiness and exercise self-restraint within their marriage [תורה תמימה].
Commentators offer different ways to understand the dual nature of this blessing. The primary approach suggests that the idea is simply repeated for emphasis, with both concepts conveying the exact same message of divine favor [רד״ק, מצודת דוד, ביאור שטיינזלץ]. Conversely, another perspective draws a sharp distinction between the different stages of raising a family. In this view, older children represent a permanent and enduring heritage given out of love and closeness to God in order to establish future generations. Meanwhile, young infants, or the specific miracle of a barren woman conceiving, serve as a direct reward and compensation for a person's good deeds and merits [מלבי״ם].
Beyond the literal family unit, there is also a spiritual dimension to this concept. In an allegorical sense, a person's true offspring are not biological children, but rather the students they teach and guide throughout their life, who are considered exactly like their own family. In this same light, the ultimate internal reward is the spiritual compensation for the Torah a person studies, deeply internalizes, and guards within their heart [רש״י].