How do we know God's saving grace is for the elect?

Ephesians 1 makes it clear that God's saving grace is directed towards His elect, the chosen ones in Christ. Specifically, Ephesians 1:4-5 articulates, 'According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love: Having predestinated us unto the adoption of children by Jesus Christ to himself.' This passage highlights that God's grace is intentional and purposeful for those He has chosen. Moreover, the Good Shepherd lays down His life specifically for the sheep (John 10:11), further illustrating the particularity of Christ’s atonement for His elect.