Existentialism is the worldview based on the philosophy of "I exist therefore I am". The deceptive thinking points us to believing that all things center around the "I".
God is real because "I" experience Him, because "I" experience things that lead me to the conclusion thinking life is good and evil, there is a supreme being that controls these things, I am not that supreme being, therefore there is a god, I believe in God. My believing drives me, whether out of curiosity or duty, to know what this God has ordained, after all, He is God.
Existentialism sets up persons with this thinking. When suffering, tragedy occur or when tough questions, seemingly out of joint events are experienced...an existentialist's faith is shaken. The world is thrown off kelter. What the person knows and believes comes into question, subject to even self skepticism, and in worst scenarios, even to self destruction.
In contrast, Christian theistic worldview bases all things from revelation from an external, absolute source. The reason why I know I exist is because the Bible tells me I am created. The reason why I know there is a God is because He chooses to reveal Himself to me. My knowledge of Him is not based on experience and reality, it is based on revelation. Experience and reality are consequences of revelation, meaning, I have experiences and I know reality because I have revelation. Persons with this worldview when going through crisis, trauma, or assailed with unanswerable question/doubts would go back to the tangible source of revelation, the Word of God, as an anchor to hold them steady.
Though a thin line, the distinction is highly significant. A person's view of God and ability to know God on a personal level is determined by where he/she believes this knowledge comes from and how it is attained. Existentialism limits the knowing of God to the self's ability to discover and know while Christianity opens opportunities to discover and know God in infinite levels through revelation.
There is a children's song that goes "Jesus loves me this I know, This I know because the Bible tells me so." An anchor. The reason why enemies of Christ primarily go after discrediting or even casting doubt on the Bible and its authenticity.
But no scholar has ever succeeded in proving the Bible false. It is actually a documented fact that top scholars and respected professionals in their field who have set out to disprove the authenticity and truth of the word of God have they themselves become the staunchest defenders of the Christian faith.
The prophecies that have been realized, historic facts and evidences verified archaeologically, prophecies made long ago coming true today, scientific facts explained thousands of years ago proven today with modern technology...established the Bible for them as undeniable, unquestionable truth.
One could very subtly and subconsciously be led to holding an existentialist worldview as society, media, and culture is permeated and shaped with existentialist philosophy for the last few centuries. Especially Christians as they are the most attractive target of the enemy. Lest one falls, a Christian must guard against corruption of thought and attacks to the very foundation and core of his/her worldview -- the Bible is real and authentic, and all the things I know, I know because the Bible tells me so.
"Your word is a lamp to my feet
And a light to my path." (Psalm 119:105 NASB)
