Those who are saved have only God to thank; those who are lost have only themselves to blame. God gets all the credit for man's salvation; the unsaved man must take full responsibility for his eternal damnation. The saved person thankfully says, "I'm in heaven because of God!" The lost person must truthfully say, "I'm in hell because of me!" Those who are damned will never be able to blame God or say, "I'm damned because God did not choose me." Their damnation is based not upon God's rejection of them but upon their rejection of God (Mk. 16:16; Jn. 5:40; 2 Thes. 2:12).
Man does not contribute to his own salvation. It is the work of God, "not of works lest any man should boast" (Eph. 2:8-9). God does not contribute to man's unbelief. That is man's work. God alone must do the saving. Man must do the believing. God must get all the glory and all the credit: "That no flesh should glory in His presence....That, according as it is written, He that glorieth, let him glory in the Lord" (1 Cor. 1:29-31). Unbelieving man must take the blame. The believer saved by grace can gratefully sing, "To God be the glory great things He hath done!" "Oh to grace how great a debtor daily I'm constrained to be!"
Like the Trinity, the Doctrine of Election must be accepted by faith!