The tense of the verb points out the time that is defined in the sentence.
Verb tenses provide information about when things happen.

The simple tenses express the basic present, past, and future.

Simple Present:

A simple present tense verb helps make a statement.

Jesus loves us so much that he died on a cross for us.

Use the simple present tense to describe an activity.
God listens to our prayers.

Simple Past:

A simple past tense verb simply describes something that happened.

Jesus died on a cross to save us from sin and death.

Future:

A future tense verb is a simple present tense verb used with the helping verbs: will or going to.

Without Jesus in my heart, I will seek to fill the void in my life with what the world offers me.

For the Son of Man is going to come with his angels in the glory of his Father....Matthew 16:27.

Perfect Tenses

In the perfect tenses, there is often a relationship between the past and the present.
These tenses provide more information about the timing and sequence of events.
Perfect tenses are used with helping verbs: has, have, or had.

There are three perfect tenses (present, past, and future).

Present Perfect:

The present perfect reflects the past, but its reflection on the past connects the past to the present. The present perfect is often used to express a past event that has present consequences. The events described by present perfects are not necessarily completed.
Let's compare it with the simple past which tells only that something happened in the past.

1. Jesus saved many people on Earth.
2. Jesus has saved many people on Earth.

The past tense "saved" is used in both sentences above.
The first sentence simply expresses an action that occurred in the past.
The meaning is changed in the second sentence with the use of "has."
The second sentence tells us about the saving of people in the past including the present time and continuing into the future.

The present perfect tense can express an action which has begun in the past, continues to the present, and may continue into the future.

...God, who has saved us and called us to a holy life, not because of anything we have done but because of his own purpose and grace. 2 Timothy 1:8-9.

The Word of God has brought many people closer to God and continues to assist people in developing a close relationship with Jesus.

We may also use the present perfect tense to talk about a change or new information:

"I've become a new creature with a renewing of my spirit through Jesus Christ." (Before knowing Jesus, I wasn't "born again" of the spirit, but now I am.)

You CANNOT use the Present Perfect with specific time expressions (yesterday, one year ago, last week, when I was a child, when I lived in Japan, at that moment, that day, one day, etc.).

The difference between the Simple Past Tense and the Present Perfect Tense:

A Simple Past statement: Jesus rose into heaven.

Using the Present Perfect Tense: Jesus has risen into heaven. (The emphasis here is on the present, resulting from the fact that the person speaking has present evidence that it occurred).

The perfect tenses use the past participle forms of verbs. These forms are listed in complete dictionaries.
Look up the present tense verb "ring" and you will see: rang (past), and rung (the past participle form) used with has/have in the present perfect tense.

Incorrect: I have ringed the bell. Or: I have rang the bell.
Correct: I have rung the bell.

Past Perfect:

The past perfect tense expresses action in the past before another action in the past, or to express the result of an action in the past because it is important in the present.

If you talk about something in the past and you want to talk about something that is connected to it and happened before it (i.e. it is more in the past than the past you are speaking about), then you can use the past perfect (had with the past participle). The past participle used with the "helping" verb (had) happened before something else in the past.

Jesus sent the Disciples to teach the people of the world what he had taught them.
The past perfect tense ("had taught") indicates the earlier of two actions, and the simple past tense ("sent") indicates the more recent action.

The Israelites and Moses had wandered in the desert for forty years, before they went into the promised land (They wandered then they went into the land).

"The Israelites and Moses wandered in the desert for forty years."
This sentence simply states a past event without connecting it to the present or another past event.

Again, use the helping verb in the past tense ("had") to create the past perfect tense.

A number of people saw Jesus after he had risen into heaven.
The past perfect tense explains the sequence of the two past events: Jesus rising (the earlier event) and then people seeing him.

"Then Peter remembered the word Jesus had spoken...." Matthew 26:75.

"They had gone to the movies before they went home."
The past perfect tense ("had gone") indicates the earlier of two actions. The simple past tense ("went") indicates the more recent action.

Finally, here's some past perfect tenses with helping verbs in sentences expressing condition and result:

If I had gotten up at 8:00, I would have arrived at church on time.

George Washington would have been president for a third term, if he hadn't rejected the offer.

Future Perfect:

The future perfect tense expresses an action or actions in the future before another action in the future using will + have. The word will expresses the future.

Jesus told Peter,

"Before the rooster crows you will have denied me three times."

By Sunday noon, I will have gone to church.

Here's one more example using the helping verb in the present tense to create the future perfect tense:
The church bells will have rung for ten minutes before the worshippers arrive.

Review

Simple Present: Jesus saves us from sin and death.
When presenting a statement of fact, use the simple present tense.

Simple Past: Jesus saved many people while He was on Earth.

Present Perfect: Jesus has saved many people (Including the present time with the past, Jesus has saved many people).

Past Perfect: Jesus had saved many people, before He ascended into heaven.
(Jesus saved many people then He ascended into heaven.)

Future: Jesus will save many people.

Future Perfect: Jesus will have saved many more people by the time He comes again (After Jesus died he rose into heaven, but through the Word of God many more people will be saved before He comes again).