Why was Prophet Muhammad(saw)’s Father Called “Abdullah (slave of Allah)”?

Questions have been asked as to why the name Allah was known BEFORE Islam was revealed to the Prophet Muhammad(saw). Typically, our Christian missionary friends have been spinning this as to mean Allah was a pagan god as the pagan Arabs knew of the word “Allah” before the coming of the Prophet and Islam? The Holy Quran states: "And see your abasement among those who fall prostrate." According to the commentary of "Madarik", "Jamal," etc. the above verse translated correctly would read: "I see the genealogy of your parents and ancestors all of whom were Believers." Believers, meaning that they believed in One Allah and were true devotees. The genealogy here refers to the chain from Prophet Adam(as) to Prophet Abdullah(as). A Tradition extracted from Bukhari found in Miskhaat, under the Chapter "Fazaa'il Syedul Mursaleen," contains the following words of the Holy Prophet Muhammad(saw): "I have been sent from the best group of the children of Adam, from one group to the next, till I am in that group which I am." Allama Al-Suyuti in his book "Kitaabut Ta'zeem was Sunnat", reports from "Dalaa'il Nabuwat" by Abu Naeem, that at her last moments, the mother of the Holy Prophet(saw), Sayyidah Aminah(as), looked at him wistfully at the plight of his orphanhood and read the following couplet: "O my son! May the Almighty Allah bestow blessings upon you, I am sure that you are from your Lord a Prophet to all creation, And that you will administer and spread Islam from Mecca to all Arab and non-Arab, Almighty will save you from worshipping idols, And the Religion of Ibrahim will spread through you." She then recited another verse: "I will pass away yet my remembrance will continue, For I have left behind me a perfect model, a perfect son." From the above verses, even her faith and belief in the Religion of Hazrat Ibrahim(as) has been proven and is an indication of her perfect belief in One Allah. Before the arrival of the Holy Prophet(saw), there was great joy and uproar in Arabia. Various conversations and debates centred upon the qualities and description of the forthcoming Prophet. The father of Rasoolullah(saw); Sayyid Abdullah(as), witnessed and also experienced many strange phenomenons. His mother also witnessed strange things during her pregnancy as well as the time of his birth. During her pregnancy, in every month a different Prophet used to appear to her in her dream describing to her of the wonderful and glorious attributes of her expected child, the Holy Prophet Muhammad(saw). Once, the midwife, Sayyida Halima(r), in a state of apprehension, described to Bibi Aminah(as) the splitting of her son's chest. Sayyida Aminah(as) replied that she should not be afraid as her son was the true and Last Prophet and that the Shaitaan would not be able to harm him in any way. So how is it possible to refer to her as a disbeliever after she had witnessed all the strange happenings and wonderful experiences? It is emphatically impossible. The Holy Quran states: "We never punish until We have sent a Messenger." The Pure Message or a Messenger never reached both of Rasulullah's(saw) parents, so how could they be punished? Yes, without doubt, they believed in the Religion of Prophet Ibrahim(as), that is, in One Allah. Yet, as history proves, the Divine Books at that time had been misinterpreted and tampered with by human beings. The criterion of being called a person of faith at that time was strictly to believe in One God, which the parents of Rasulullah (saw) believed in. It would be unfair to, therefore, call them disbelievers.