ومن الذين قالوا إنا نصارى أخذنا ميثاقهم فنسوا حظا مما ذكروا به (5:14) بالانجليزي

(5:14) We also took a covenant from those who said: 'We are Christians'; *36 but they forgot a good portion of the teaching they had been imparted with. Wherefore We aroused enmity and spite between them till the Day of Resurrection, and ultimately Allah will tell them what they had contrived.

Tafseer Abu-al-A'la Maududi

Page 110 English Traditional

*36). Some are of the opinion that the word Nasara (meaning Christians) is derived from Nasirah (Nazareth), the birth-place of the Messiah. In fact this word is not derived from Nasirah (Nazareth) but from the word nusrah, and the basis of this derivation is the question posed by the Messiah to his disciples: 'Who are my supporters (ansari) in the way of God?' In response to this they had said: 'We are the supporters (ansar) (in the way) of God.' Christian authors have been misled by the resemblance between the words Nasirah and Nasara into believing that the name of the sect founded in the early history of Christianity, and contemptuously characterized as either Nazarenes or Ebonites served as the basis of the Qur'anic designation of the Christians. But here the Qur'ijo categorically states that they had declared that they were 'Nasara' and it is obvious that the Christians never called themselves 'Nazarenes'.
In this connection it should be recalled that Jesus never called his followers 'Christians' for he had not come to found a new religion named after him. His mission was to revive the religion of Moses and of all the Prophets who preceded him as well as of the one who was to appear after him. Hence, he neither formed any cult divorced from the Israelites and the followers of the Mosaic Law nor designated his followers by any distinctive name. Likewise, his early followers neither considered themselves to be separate from the Israelite community nor developed into an independent group nor adopted any distinctive symbol and name. They worshipped in the temple of Jerusalem along with other Jews and considered themselves to be followers of the Mosaic Law (see Acts 3:1-10; 21: 14-15,21). Later on the process of alienation began to operate on both sides. On the one hand, Paul, one of the followers of Jesus, declared independence from the Mosaic Law holding that faith in Christ was all that one needed for salvation. On the other hand, the Jewish rabbis declared the followers of Christ to be heretics and excommunicated them. Despite this, for some time the new sect had no distinct appellation of its own. The followers of Christ variously described themselves as 'disciples', as 'brethren', as 'those who believed', and as 'saints' (see Acts 2: 44; 4: 32; 9: 26; 11: 29; 13: 52; 15: 1; 23: 1 and Romans 15: 25 and Colossians 1: 2). The Jews sometimes designated them as 'Galileans' and as 'the sect of Nazarenes' (see Acts 24: 5; Luke 13: 2). These nicknames, which were originally contrived in,.ojder to ridicule them, referred to Nazareth, the home town of Jesus in the district of Galilee. These names, however, did not gain sufficient popularity to become the permanent names of the followers of Christ. They were called 'Christians' for the first time by the people of Antioch in 43 A.D. or 44 A.D. when Paul and Barnabas went there and began to preach their religion (Acts 11: 26). This appellation was flung at them by the opponents of the followers of Christ precisely in order to tease them by using an appellation which was unacceptable to them. But when their enemies began to call them consistently by this name their leaders reacted by saying that if they were called Christians because of their allegiance to Christ they had no reason to be ashamed of it (1 Peter 4: 16). It was thus that the followers of Christ also gradually began to call themselves by the same name which had originally been conferred upon them sarcastically. In the course of time the Christians ceased to realize that theirs had originally been a derogatory appellation chosen for them by outsiders rather than by themselves.
The Qur'an, therefore, does not refer to the followers of Christ as Christians. It reminds them rather that they belong to those who responded to the query of Jesus: 'Who are my supporters (ansari) in the way of God?' by saying that they were his ansar (supporters) in God's cause. (See Surah al-Saff 61: 14 - Ed.) It is an irony of fate that far from feeling grateful at being referred to by a dignified appellation Christian missionaries take offence at the fact that the Qur'an designates them as Nasara rather than as 'Christians'.