Albert Barnes Commentary Isaiah 46:4

"and even to old age I am he, and even to hoar hairs will I carry [you]; I have made, and I will bear; yea, I will carry, and will deliver." — Isaiah 46:4 (ASV)

And even to your old age, I am he — or rather, I am the same. I remain, unchangeably, with the same tenderness, the same affection, the same care. In this, the care of God for his people surpasses that of the most tender parent and the kindest nurturer of the young. The care of the parent naturally diminishes as the child reaches adulthood, and the parent is usually taken by death before the son or daughter, who was the object of so much solicitude in infancy and childhood, reaches old age.

But it is not so with God. His people are always the objects of his tender solicitude. Age does not make them less dependent, and experience only teaches them more and more their need of his sustaining grace.

The argument here is that he who had watched over the infancy of his people with so much solicitude would not leave them in the vulnerabilities, infirmities, and trials of the advanced years of their history.

The doctrine is:

1. That his people always need his protection and care.
2. That he will never leave nor forsake them.
3. That he who is the God of infancy and childhood will also be the God of old age, and that he will not leave or forsake his people, who have been the objects of his care and affection in childhood, when they become old.

Although this passage refers primarily to a people or a community as such, I see no reason why the principle should not be regarded as applicable to those who are literally aged.

They need the care of God no less than childhood does. If they have walked in his ways in the vigor and strength of their life, he will not cast them off when they are old and gray-headed. Hoary hairs, therefore, if found in the way of righteousness, may trust in God; and the second childhood of man may find him no less certainly a protector than the first.