Translation:

78. And strive in His cause as ye ought to strive (with sincerity and under discipline): He has chosen you and has imposed no difficulties on you in religion; it is the cult of your father Abraham. It is He Who has named you Muslims both before and in this (Revelation); that the Apostle may be a witness for you and ye be witnesses for mankind! So establish regular Prayer give regular Charity and hold fast to Allah! He is your Protector the Best to protect and the Best to help!

Notes (Tafseer)

2861. As far as the striving is concerned with Jihad in the narrow sense, see the limitations in n. 204 to ii. 190 and n. 205 to ii. 191. But the words are perfectly general and apply to all true and unselfish striving for spiritual good.

2862. The Jews were hampered by many restrictions, and their religion was racial. Christianity, as originally preached, was a hermit religion: "sell whatsoever thou hast" (Mark x. 21); "take no thought for the morrow" (Matt. vi. 34). Islam, as originally preached, gives freedom and full play to man's faculties of every kind. It is universal, and claims to date from Adam: father Abraham is mentioned as the great Ancestor of those among whom Islam was first preached (Jews, Christians, and Arabs).

2863. Before: see Abraham's prayer in ii. 128. In this revelation: in this very verse, as well as in other places.

2864. See ii. 143, and notes 143 and 144. As the Prophet is a guide and exemplar among us, so Muslims ought to be exemplars amongst mankind. The best witness to Allah's Truth are those who show its light in their lives.