John 3:
The intent of the Cross of God was not to save all lost sinners, but to save only those whom he would draw and call and bring to Jesus!
Don't forget the effects of sin on nature and all living things. Since Jesus conquered death and hades by His resurrection, then something powerful happened when our Creator became our Redeemer on the cross.
So yes... it is by the power of the ransom of the cross that He can save all sinners
BUT it can only be applied to those that believe in Him.
That means for the unbelievers out there, the power to save them is still available and all they have to do is believe in Him.
John 3:15 That whosoever believeth in him should not perish, but have eternal life. 16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. 17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved. 18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
John 1:12 But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name: 13 Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
Once saved, new believers can learn of Him in His words and all His promises to us in living that reconciled relationship with God through Jesus Christ by trusting Him to be their Good Shepherd to help them lay aside every weight & sin in following Him so they can be received as a vessel unto honor in His House by the Bridegroom when He comes at the pre great trib rapture event.