The Bible asks us not to "deviate from the simplicity in Christ". I see that in Christianity, salvation is often made to be something more complex than what it is. I think it's very simple. Repent and believe in Jesus Christ our God, in His death for the redemption of our sins and His resurrection. That's it. Would you agree or not and why?
I agree that "salvation is often made to be something more complex than what it is."
John 6:40 For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.”
If we dare to understand salvation based on Jesus' sayings in the Gospel, it will be more straightforward; I do not use simple or simplicity - still it is not that simple that need no musing.
I will elaborate four terms from the quote: redemption, salvation, repent, death and resurrection.
redemption
I find there's no "redemption" in Jesus' sayings. That "redemption" is very popular in Christian's believe, however, likely redemption is not the key point of salvation.
salvation
I find John 17:3 is the terminal of salvation.
Now this is eternal life: that they know you the only true God, and Jesus Christ, whom you have sent.
The last words of
John 6:40 say "I will raise them up at the last day". Why He is waiting for the last day? Because (referring to John 16:12-15 ) He is awaiting the Church to come to John 17:3.
As we read
Matthew 16:16, Simon Peter answered, “You are the Messiah, the Son of the living God.”
Very likely the Church is now more or less at the same position with Peter; the Church is maintaining Peter's answer.
Jesus gave the keys of heaven to Peter (the Church);
Matthew 16:19 "I will give you the keys of the kingdom of heaven".
Jesus is awaiting for the Church to turn the key (John 17:3 ) on; do believe
John 14:7 If you really know me, you will know my Father as well. From now on, you do know him and have seen him.
For our salvation, let's move forward from "redemption" to "know the only true God".
repent
For me, repent means to switch from believing or worshiping "our perceived God" to knowing and worshiping "the only true God"; Jesus came to lead us to know "the only true God".
We are the prodigal son and the heir of the prodigal son ( Luke 15:11-32 ), walking our personal enjoyment with a consequence that we lost the knowledge of our origin, then we have to crawl to regain the knowledge (the human history say: from being animist, to polytheist, to monotheist). Jesus came to show the way and to be the way. Without Jesus we will never regain our knowledge. We will only come to the "perceived God".
See also, Luke 13:3, Luke 13:5, John 8:24, Matthew 11:27, John 17:3.
It will be easier to understand "repent" if we understand John 3:18, John 3:5, John 3:11, Matthew 11:14; those verses lead us to John 8:24.
death and resurrection
Jesus' miracles were given to attract people to Him.
His death and His resurrection likely is His miracle - His final message for humanity to come to be His disciples and seriously to follow His teachings which lead to human salvation.
John 14:6 says that we have to follow His way (by stepping through His path / His teachings), (under guidance of the Spirit) the teachings will lead us to the truth, and the truth will bring a man into life (eternal life, John 17:3 ).
Again, let's move forward from "redemption" to "know the only true God".
Jesus is awaiting for the Church to turn the key (John 17:3) on.
No need to be complicated. Our Father in heaven is good, He is open to cheer our repentance - switching from our "perceived God" to "the only true God".
Worshiping our "perceived God" is against His will, it is the "main sin" ( John 8:24 ); other sins are just byproducts.