My Soul Is As A Weaned Child

[Mr. M]

Isaiah 28:9 Whom shall He teach knowledge?
and whom shall He make to understand doctrine?
them that are weaned from the milk, and drawn from the breasts.

The question proposed in the verse is immediately answered by way of metaphor.
The question then becomes, what does this mean, to be:
"weaned from the milk, and drawn from the breasts"?

Hebrews 5:
12 For though by this time you ought to be teachers,
you need someone to teach you again the first principles of the oracles of God;
and you have come to need milk and not solid food.
13 For everyone who partakes only of milk is unskilled in the word of righteousness, for he is a babe.
14 But solid food belongs to those who are of full age, that is, those who by reason of use
have their senses exercised to discern both good and evil.

The quotation from Hebrews 5 is cited because the most
immediate answer is to say a mature Christian;
leaving to debate what constitutes "a mature Christian"?

The answer to the question proposed in Isaiah is answered
by David in the Psalms:
131:
1 Lord, my heart is not haughty,
Nor my eyes lofty.
Neither do I concern myself with great matters,
Nor with things too profound for me.
2 Surely I have calmed and quieted my soul,
Like a weaned child with his mother;
Like a weaned child is my soul within me.
3 O Israel, hope in the Lord
From this time forth and forever.

This is the testimony of a mature Christian.