Why can't I understand the scriptures?

God has purposely hidden His words in mystery (Romans 16:25), so that men who strive to understand the Scripture through their own worldly knowledge can never come to know the truth (II Timothy 3:7). The Gospel preached by those who are not sent by God is called by the Apostles “another gospel?(Galatians 1:6-7). And the use of the Gospel which deviates from the truth or from its true meaning will ineluctably lead to perdition (II Peter 3:15-16).