Die Religion ist wichtig.

Because Religion is a feminine noun in German. In the nominative singular, feminine nouns use the article die.

So you learn the noun as:

die Religion = religion / the religion

In German, grammatical gender is something you usually have to memorize with each noun.

Here, die is the definite article, so it corresponds to the in English.

So literally, the sentence is:

Die Religion ist wichtig.
The religion is important.

But depending on context, German often uses the definite article where English might use no article, especially with general ideas or abstract nouns. So it can also sound like a general statement about religion.

Because all nouns are capitalized in German.

So:

• die Religion
• das Buch
• der Mann

This is one of the most noticeable spelling differences from English.

Ist is the third-person singular form of the verb sein (to be).

The subject is die Religion, which is singular, so German uses:

• ich bin = I am
• du bist = you are
• er/sie/es ist = he/she/it is

Since die Religion is a singular noun, it takes ist.

No. After verbs like sein (to be), adjectives usually stay in their basic form.

So:

• Die Religion ist wichtig.
• Das Buch ist interessant.
• Der Mann ist müde.

This is called a predicate adjective. Predicate adjectives do not take adjective endings in German.

By contrast, adjective endings appear when the adjective comes before a noun:

• die wichtige Religion
• ein interessantes Buch

This is the normal German word order for a basic statement:

Subject + verb + complement

So:

• Die Religion = subject
• ist = verb
• wichtig = adjective/complement

German main clauses usually put the conjugated verb in the second position. In this sentence, the subject comes first, so the verb comes right after it.

Sometimes, but Die Religion ist wichtig is the more standard and natural form for a simple learner sentence.

Using or omitting the article with abstract nouns in German can depend on style, meaning, and context. German often uses the article more readily than English does.

So for a beginner, it is safest to learn:

die Religion
Die Religion ist wichtig.

Good question. Die can mean:

• feminine singular nominative
• plural nominative

In this sentence, it is clearly singular because:

1. Religion is a singular noun here.
2. The verb is ist = is, which is singular.

If it were plural, you would expect:

Die Religionen sind wichtig.
The religions are important.

A simple pronunciation guide:

• Religion ≈ reh-lee-ghee-OHN
  
  • The stress is on the last syllable: -on
• wichtig ≈ VIKH-tikh or VIK-tikh
  • w sounds like English v
  • ch in wichtig is the soft German ich sound

So the whole sentence sounds roughly like:

dee reh-lee-ghee-OHN ist VIKH-tikh

It is in the nominative case because it is the subject of the sentence.

You can identify it by asking: What is important?
Answer: die Religion

So:

• die Religion = nominative subject
• ist = verb
• wichtig = predicate adjective

Almost:

• Die = the
• Religion = religion
• ist = is
• wichtig = important

So the literal translation is:

The religion is important.

But depending on context, the more natural English meaning might simply be:

Religion is important.

That difference happens because German and English do not always use articles in exactly the same way.