So, if our prayers are in fact enough and what God really desires, what is the actual need for the crucifixion?
Hebrews 2:14 and 1 John 3:8 reveals why The Son was born in the flesh to die on the cross. It was to defeat death and the devil.
Those 2 Scriptures reveal that the power of death was assigned to the devil, and that the devil sinned from the beginning, and for this reason was The Son of God manifested in order to defeat all that for us.
In Galatians 3:22, Apostle Paul says the Scriptures have concluded us all under sin so that the Promise by Faith might be to those who believe on Jesus Christ.
So that kind of... points to the need to know how sin and death came about with what Satan did in the beginning. Per the parable of Ezekiel 28, God reveals that He originally created Satan perfect in his ways. It was Satan's job as a covering cherub to guard God's throne. Instead, Satan coveted God's throne and desired to be God. That is how he fell. And that actually was the very 1st... sin.
God assigned the result of Satan's sin then to be death, already judging and sentencing Satan to perish in the future "lake of fire", along with death. And Satan was given the power of death. This means that there is no evil with our Heavenly Father at all. All evil and sin originates from the devil. The devil originally followed God, until iniquity was found in him. However, for this present world, God will 'use' Satan and evil as a punishing rod upon the rebellious, even though He is still not the author of evil (thus many folk's misunderstanding of Isaiah 45:7 which is actually God saying He causes calamity upon the rebellious for 'this' world).
So by Lord Jesus Christ sacrificing Himself upon His cross for those who believe on Him and The Father, God chose that way to defeat the devil and death for us. And also for this reason, starting in Genesis, the devil tried many times to prevent the Family of Christ (the Seed He was to be born through) from existing. (I believe the devil knew if Jesus were born and died on the cross, that would seal the devil's fate towards destruction in the "lake of fire".)
These things are not taught in most Churches today. But they are part of God's Word, and are written and hinted at. The powers in this world exist to make the believer doubt these things in The Word of God so that they remained confused about what is really going on in this present world.