To diagram the sentence "The Lord is good to all," you would use a traditional sentence diagram. Here's a step-by-step breakdown:

1. Identify the Subject and Predicate: The subject is "The Lord," and the predicate is "is good to all."

2. Diagram the Subject: Draw a horizontal line. Above the line, write "The Lord." "The" is an article modifying "Lord," so place it slightly below and connected to "Lord" with a slanted line.

3. Diagram the Verb: Draw a vertical line intersecting the horizontal line representing the subject. On this vertical line, write "is," the verb.

4. Diagram the Predicate Adjective: "Good" is a predicate adjective describing the subject. Draw a slanted line extending to the right from the verb "is." Write "good" on this slanted line.

5. Diagram the Prepositional Phrase: "to all" is a prepositional phrase modifying "good." Draw a slanted line extending down from "good." Write "to" at the bottom of this line. Then, draw a short horizontal line extending to the right from "to." Write "all" on this horizontal line.

The final diagram would look something like this (represented textually as best as possible):

       The       
        |
        \
The Lord --is--good--to--all
                 |
                 \
                 all

This diagram visually represents the grammatical relationships within the sentence, showing how "The Lord" is the subject, "is" is the verb, "good" is the predicate adjective describing the Lord, and "to all" modifies "good." The diagram clearly illustrates the sentence's structure and the function of each word.