How do we know that only some are chosen to run the race of salvation?

According to the doctrine of sovereign grace, as supported by Ephesians 1:4-5, God predetermined those who would be adopted as His children in Christ. This election is not based on foreseen faith or works but is solely by God's grace. Romans 8:29-30 further elaborates on this, confirming that those whom He foreknew, He also predestined to be conformed to the image of His Son. In the context of running the race, this means that only those whom God has called and quickened by His Spirit will have the faith necessary to persevere until the end. The assurance of perseverance is found in the fact that God upholds His elect in this race, ensuring they remain steadfast.