Additional commentary on the Biblical Meaning of 50 *
The number 50 is used 154 times in scripture. Fifty is connected with the coming of the Holy Spirit.
On the Wave Sheaf Offering Day (Leviticus 23:9-11), Jesus ascended to heaven for the first time, to be accepted by the Father as the first of the firstfruits. Beginning with that day, there is a 50-day count to Pentecost, the Feast of Firstfruits, when the Holy Spirit was first poured out upon the Church — the firstfruits of the spiritual harvest. God the Father did not send the Holy Spirit until Christ, as the new High Priest, placed His blood (represented by 30) on the altar of atonement (represented by 20) — which equals the number fifty and points to Pentecost.
Pentecost is also the 8th day of the 7th week in the 7-week count to Pentecost; it is also the first day of the 8th week. As such, the numbers 8 (new birth) and 50 (the day / year of redemption) picture the first resurrection of all who are Christ’s at His coming — the day they are "born again" from flesh to spirit (1Corinthians 15:20-23, 35-55; John 3:3-12; Revelation 14:14-16; 20:4-6).
The Meaning of Numbers: The Number 51
This is the number of Divine revelation, for there are 24 books in the Old Testament, and 27 books in the New Testament, making 51 in all.
This is, of course, reckoning the Divine separation of the books, as exhibited in the manuscripts, which form our only authority, and not reckoning according to man's manipulation of them; for both Jewish and Gentile fancies make quite a different and conflicting number.
The Meaning of Numbers: The Number 65
In the Bible the number sixty-five, being a multiple of thirteen (13 x 5 = 65), is specially associated with Ephraim (see Isaiah 7:8), and marks the apostasy of that Tribe. This apostasy, which began in Judges 17, afterwards extended to the Ten Tribes of Israel kingdom, which is frequently spoken of therefore under the name of Ephraim:
"Within sixty-five years Ephraim will be broken, so that it will not be a people." (Isaiah 7:8, NKJV)