Why do Paul the apostle and so many Church Fathers strongly stress the concept of ‘dying with Christ’?

The apostle Paul says, “I have been crucified with Christ; it is no longer I who live, but Christ lives in me” (Gal. 2:20). He understood that whoever suffers, is crucified, dies, and is buried with Christ, will enjoy the sweet fragrance of Christ. Whoever attaches himself to the crucified Christ and becomes one with Him no longer seeks the pleasures of the world, but rather takes pleasure only in being crucified, buried, and risen with Christ. For him, the bitterness of the world is transformed into sweetness. He takes the bitter myrrh that embalmed the body of Christ in the tomb and anoints his own body with it, and thus carries about the sweet fragrance of Christ wherever he goes (2 Cor. 2:15).

St. Gregory of Nyssa says, “Hence, the person who intends to dedicate himself to the worship of God will not be frankincense burned for God unless he has first become myrrh— that is, unless he mortifies his earthly members, having been buried together with the one who submitted to death on our behalf and having received in his own flesh, through mortification of its members, that myrrh which was used to prepare the Lord for burial. When these things have come to pass, every species of the fragrances that belong to virtue—once they have been ground fine in the bowl of life as in some mortar—produces that sweet cloud of dust, and he who inhales it becomes sweet-smelling because he has become full of the fragrant Spirit.”⁴⁵²