A profound sense of total dependence on God's care accompanies a person from the very dawn of their existence. Relying completely on God means looking to Him for all support, guidance, and the fulfillment of every life need.
The earliest stages of life highlight this deep reliance. The primary approach among commentators is that the early periods of development before and during birth work together to describe infancy. However, a more specific view notes a distinction between the two stages: one represents the exact moment of birth into the world, while the other refers to the even earlier period of pregnancy [מלבי״ם]. Naturally, a newborn infant lacks the awareness to actively place its trust in God. Therefore, this act of surrender and gratitude is actually performed by the parents, who entrust their child's fate to heaven [רד״ק].
God's care for a newborn takes shape in two distinct but complementary ways. The primary approach among commentators is that this protection operates quietly through the natural world. God provides the mother with the nourishment and ability to nurse, and He grants the infant the strength to feed and grow. Ultimately, the child's true reliance is on God rather than the mother [אבן עזרא, רד״ק]. Conversely, another perspective views this through the lens of orphanhood, whether as a metaphor or a harsh reality where a father passes away before birth [אלשיך] or a mother dies immediately after [מלבי״ם]. In such a helpless state, God steps in as the sole guardian and provider who raises the child.
On a national and historical level, this early childhood dependence serves as a metaphor for God's relationship with the Israelites. God carried and guided the tribes of Israel from the very moment they were born as a nation [רש״י]. He even watched over them during their national period of gestation, guarding them before they were finally redeemed from exile in Egypt [מלבי״ם].
Yet, it is exactly this deep, lifelong bond that makes the current suffering so deeply painful. God has acted as a close patron and guardian since the very beginning of the speaker's life. Because God's name has always been associated with him, and he has leaned on Him from his first day, his enemies now mock him with even greater cruelty when it appears that God has finally abandoned him [מלבי״ם, אלשיך].