Sometimes an entire theological discussion can hinge on a single word, so it's good to think carefully about the words you use, and consider how others are using them as well.
The words "worth" and "worthy" are two words which, while they are very similar, and come from the same root, have vastly different meanings.
The word "worth" means "value."
The word "worthy" means "deserving."
One of the words (worthy) is a binary - either you are or you are not worthy; there is no middle ground. The other is a spectrum with "worthless" at one end of the spectrum, and increasing in value from there.
It is important to note that "worthy" is an objective binary, clearly defined in scripture:
"Worth" on the other hand is a subjective scale, which varies from person to person. For example, if I had a piece of artwork which was painted by an ancestor, and had been in my family for generations, I would probably not sell it except for a significant amount of money. On the other hand, that same painting might be of very little worth to anyone else.
As an example of these words in daily life, let's see how they play out in my relations with my students. Suppose one of my students repeatedly cheats on homework and tests. When the next test day comes, I'm going to watch that student like a hawk through the entire test. Why? Because she has proved herself to be unworthy of my trust. Her behavior has not measured up to the standard for which I would give my trust.
But despite that, if that same student came to me and said, "Mr. T, if I come in before school, will you help me get my homework assignment done?" I would reply, "Absolutely!" Why? Because that student is worth a great deal to me.
One does not have to measure up in order to be of great value. Or, to put it another way, one can be of great worth, while still being unworthy.
This distinction is at the heart of the Gospel. We are not worthy of salvation and eternal life, but despite our unworthiness, we are of great value to God.
Paul emphasizes our unworthiness in verses like Romans 3:23, and we find this spelled out dramatically in the book of Revelation:
On the flip side, in two different places in the Gospel of Matthew Jesus emphasizes our great worth to God by pointing out how much he cares for the birds, and then comparing that to our worth to God:
The Old Testament also emphasizes our worth to God; Psalms 8:3-5 points out the high regard God has for humanity within the scope of his creation, and when God speaks out against murder, the value He places on humanity is at the heart of his instruction:
It's interesting to note that some dictionaries and thesauri list "value" as a synonym for the verb "to love." To love someone is to value them. Although people might not consciously think of love in those terms, at a deep level, we all understand that what we love we consider to be of great worth.
Thus, we could answer this question: "How great is our value in the eyes of God?" by answering: Our worth (value) is so great that He sent His one and only Son to face death on the cross on our behalf, in order that we might have salvation in Him, even though we were not worthy.
So why does it matter that we understand the difference between "worth" and "worthy"? Because when we, as teachers, state that we are not worthy, our listeners may very well hear us as saying that they are worthless. This is the antithesis of gospel; we are of great worth to God. The notion of human unworthiness must be held up as distinct from our value in the eyes of God. The Gospel melds both of these concepts into one beautiful message of hope. Leave one out, and you have a message of false hope (God accepts me because I'm good enough); leave the other out and you have a message of an unloving God, which leads to despair.