More words you do not understand much like the disciples did not understand the gospel until pentecost.
Here I will use a Calvinist as your hostile witness once again. Maybe you will repent now.
To see - Rather, he earnestly and joyfully desired that he might see. To see here means to have a view or distinct conception of. It does not imply that Abraham expected that the Messiah would appear during his life, but that he might have a representation of, or a clear description and foresight of the times of the Messiah.
My day - The, day of the Messiah. The word "day," here, is used to denote the time, the appearance, the advent, and the manner of life of the Messiah.
Luke 17:26; "as it was in the days of Noah so shall it be also in the days of the Son of man." See
John 9:4;
Matthew 11:12. The day of judgment is also called the day of the Son of man, because it will be a remarkable time of his manifestation. Or perhaps in both those cases it is called his day because he will act the most conspicuous part; his person and work will characterize the times; as we speak of the days of Noah, etc., because he was the most conspicuous person of the age.
He saw it - See
Hebrews 11:13; "These all died in faith, not having received (obtained the fulfillment of) the promises, but having seen them afar off, and were persuaded of them," etc. Though Abraham was not permitted to live to see the times of the Messiah, yet he was permitted to have a prophetic view of him, and also of the design of his coming; for,
1. God foretold his advent clearly to him,
Genesis 12:3;
Genesis 18:18. Compare
Galatians 3:16; "Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, and to thy seed, which is Christ."
2. Abraham was permitted to have a view of the death of the Messiah as a sacrifice for sin, represented by the command to offer Isaac,
Genesis 22:1-13. Compare
Hebrews 11:19. The death of the Messiah as a sacrifice for the sins of men was that which characterized his work - which distinguished his times and his advent, and this was represented to Abraham clearly by the command to offer his son. From this arose the proverb among the Jews
Genesis 22:14, "In the mount of the Lord it shall be seen," or it shall be provided for; a proverb evidently referring to the offering of the Messiah on the mount for the sins of men. By this event Abraham was impressively told that a parent would not be required to offer in sacrifice his sons for the sins of his soul - a thing which has often been done by pagan; but that God would provide a victim, and in due time an offering would be made for the world.
Was glad - Was glad in view of the promise, and that he was permitted so distinctly to see it represented. If the father of the faithful rejoiced so much to see him afar off, how should we rejoice that he has come; that we are not required to look into a distant futurity, but know that he has appeared; that we may learn clearly the manner of his coming, his doctrine, and the design of his death! Well might the eyes of a patriarch rejoice to be permitted to look in any manner on the sublime and glorious scene of the Son of God dying for the sins of men. And our chief honor and happiness is to contemplate the amazing scene of man's redemption, where the Saviour groaned and died to save a lost and ruined race. Barnes
hope this helps !!!