Trinity. Prof Erickson 'Its claimed the Trinity doctrine is a very important/crucial /even basic doctrine.' Scriptures don't say so. True?

An honest look at the trinity doctrine shows it is far from scriptural. Even secular references show it was a man-made doctrine of the Catholic Church.

For example:
The first Council of Nicaea (artist’s impression) paved the way for the Trinity doctrine
“The Christian Bible, including the New Testament, has no trinitarian statements or speculations concerning a trinitary deity.”—Encyclopædia Britannica.

“The doctrine of the trinity . . . is not a product of the earliest Christian period, and we do not find it carefully expressed before the end of the second century.”—Library of Early Christianity—Gods and the One God.

“In order to articulate the dogma of the Trinity, the [Catholic] Church had to develop her own terminology with the help of certain notions of philosophical origin.”—Catechism of the Catholic Church.

Take a close look at the Bible's teaching about the identify of God, His son Jesus, and his active force, the Holy Spirit, and the answer will be evident,

The Scriptures don't use the word Trinity, but I see the teaching in there when I read.

The bible says in several places there is one God. Each of His names represent His nature.

For example, Christ means anointed and Jesus is the word. So Christ Jesus is the anointed Word. He is also called Holy Spirit because He is holy and He is Spirit. I hope I was able to help.

I read the trinity doctrine came about in the 3rd Century. I don't go by it personally. Whenever I see things that talk about God and Jesus, I just remind myself they are one until I get further understanding from God.

Christ "says so" where he tell us to baptize "in the name of the Father, and of the Son, and of the Holy Spirit."

I don't know if that quote is or is not accurate
but I strongly suspect (given the grammatical errors) that it is not accurate.

However: it certainly is true that the Bible does not explicitly teach the doctrine of trinity.
IF one has the opinion that the doctrine of trinity is a fundamental or necessary doctrine of Christianity
then it is surprising that it is not explicitly taught in any of the Biblical documents.

(Note: I am convinced that the doctrine of trinity is NOT either a fundamental or necessary doctrine of Christianity, even though I believe it is correct and that competing doctrines are incorrect.)

Scripture also doesn't say that all the essential beliefs of Christianity can be found in Scripture. That manmade tradition was never heard of by any Christian on Earth until the doctrinal chaos of Protestantism began a few hundred years ago. Jesus Christ founded one Church, said it was to remain one, and promised that one Church "The Holy Spirit will guide you into all truth", and "Whatsoever you bind upon Earth is bound in Heaven", and "He who hears you hears Me". That's where the fullness of truth can be found, in His Church. And the truths that are found in the Bible are there because that one Church compiled the Bible from its own writings.
However, Jesus Christ Himself commanded His apostles to "teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit" (Matt 28:19). And John wrote "There are three that bear record in Heaven, the Father, the Word (Jesus), and the Holy Spirit, and these three are one" (1 John 5:7-8). And all three of the divine Persons are mentioned numerous other places in the Bible, individually and collectively.

“If anyone denies that the Father is eternal, that the Son is eternal, and that the Holy Spirit is eternal: he is a heretic.”—Tome of Damasus Council, 382 A.D.

Isaiah 44:6, " Thus saith the Lord the King of Israel, and his redeemer the Lord of hosts; I am the first, and I am the last; and beside me there is no God."
Verse 24, "24 Thus saith the Lord, thy redeemer, and he that formed thee from the womb, I am the Lord that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself".
John 14:9, "Have I been so long time with you, Philip, and yet you have not known me? He that hath seen me hath seen the Father; how sayest thou then, show us the Father?" If we are to believe God exists as three divine "persons," why did Jesus not explain it when Philip said, "Show us the Father"?
Also read Colossians 2:9-10.

" If that is indeed the case, shouldn't it be somewhere more clearly, directly /explicitly stated in the Bible? "

According to who? You? Maybe you should tell God you know better!

The Trinity is not a Bible teaching. In fact, The New Encyclopedia Britannica says: "Neither the word Trinity, nor the explicit doctrine as such, appears in the New Testament, nor did Jesus and his followers intend to contradict the Shema in the Old Testament: 'Hear, O Israel: The Lord our God is one Lord' (Deut. 6:4)....The doctrine developed gradually over several centuries and through many controversies..." The New Catholic Encyclopedia states: "The formulation 'one God in three Persons' was not solidly established prior to the end of the 4th century. Among the Apostolic Fathers, there had been nothing even remotely approaching such a mentality or perspective." They admit that the teaching is not Biblical, yet, all of Christendom believe that Jesus is God because of it. Lies confuse, whereas the truth makes sense every time. I invite you to learn more about what the Bible really teaches from the international website, jw.org and Bible Teachings > Bible Questions Answered. Watch videos such as: Does God have a Name?--Exodus 6:3; Psalms 83:18--- What is God's Kingdom? --Daniel 2:44; Matthew 6:10; Revelation 11:15---Why did God Create the Earth? ---Genesis 1:20-30; Psalms 115:16 and Matthew 5:5---Why Study the Bible?---Isaiah 48:17+18 and 2 Timothy 3:16+17--If you believe what you learned, you can request your free personal Bible study online or from the next witness who knocks on your door or by visiting your neighborhood Kingdom Hall of Jehovah's Witnesses. There is never a collection taken and all are welcome. Thank you for this question.

The real and only one true scripture of GOD ,say this.
GOD is Unique, HE is the source of everything , HE begeth not nor is HE begotten and there nothing like unto HIM , the Lord of all the worlds.

Scriptures fail to mention a whole lot of essential Christian truths. So what?

By reciting the rosary each day with care, a person can know with certainty God is Triune and can better comprehend the Mystery of the Trinity.