Dear Friend ,
Eternal Salvation is by grace through faith (Eph. 2:8, 9), and it is based entirely upon the finished work of of another ( John. 19:30). Nothing which man has done , is presently doing , or will ever do can have anything to do with his enternal destiny. Man can do no more than receive by faith that which has already been done on his behalf. This is why Scripture states, " Believe on the Lord Jesus Christ, and thou shalt be saved" ( Acts. 16:31).
As being a christian and saved that christian can be a man of the world -- a person interested in the things of the world rather than the things of God, as Esau sold his birthright and considered his birthright to be of little value, he considered one meal to be more value and sold his rights as firstborn for a meal.
Christians can go the way of Esau and Lot -- having any spiritual sences and perspectives progressively dulled by the things of the world -- resulting in the thier progressively being overthrown in the land of Esau and Lot. Or they can keep their eyes fixed on the goal, dwell in the tabernacles with Abraham, Isaac, and Jacob in the high country -- "excape to the mountians" ( Gen. 19:17), having their spiritual sences and progressively strengthened -- and one day realize the rights of the firstborn.
The former is the easy life, and the latter is not so easy. In fact , the latter often becomes quite difficult. But what will be the end be? That's what matters!
To be in the wedding festivties ( Matt. 25:10 ) a christian must be a overcomer as stated in the letters to the seven Churches in (Rev.) this will enable him to claim his firstborn rights to Christ's Kingdom and the 1000 year rule. As a overcomer you must overcome the World, Saten, and the flesh.
To overcome the world you obey Christs commandments, to overcome Saten you resist him, to overcome the flesh you mortify it daily. I pray this has helped.