The answer
Christology is the topic of this passage. St. John Chrysostom is answering the question "How can it be that He is a Son, and yet not younger than the Father?In the first passage, St. John Chrysostom is describing the relation between the Father and the Son. He explains how the Son was from the beginning and is eternal like the Father, for there in no notions of time with God. The second passage is an analogy describing how the Son is begotten from the Father as radiance proceeds from the sun. The rays proceed from the substance of the sun itself and we cannot have one without the other. Both the Eastern and Western Churches adopt this belief, that the Son is begotten from the Father.
It is the issue of the Holy Spirit proceeding from the Father only or the Father and the Son that is controversial and is the cause of disagreement between all the Orthodox Churches and the Catholic Church. In 589 A.D., in the synod of Toledo, Spain, the filioque, the doctrine that claims that the Holy Spirit proceeds from the Father and the Son, was added to the Nicaeo-Constantinopolitan Creed.
Unfortunately, Rome adopted this error. The Orthodox Churches (non-Chalcedonian and Chalcedonians) believe in the procession of the Holy Spirit from the Father alone. The Bible is clear on this topic "But when the Helper comes, whom I shall send to you from the Father, the Spirit of truth who proceeds from the Father, He will testify of Me" (John 15:26).
We need to note here that the Spirit proceeds from the Father only, but is sent by the Son. "But if I depart, I will send Him to you" (John 16:7). Note: The Son will send the Spirit.
It was not out of humility that Christ did not say that the Holy Spirit was proceeding from Him. He did not because it is not the case. Why does He not refer to the Holy Spirit as processing from Him but from the Father? H. H. Pope Shenouda III says that this dogma makes two Fathers in the Holy Trinity, for there would be two origins.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)