The changes which had to be made to attract Germanic chieftains and warriors to the faith of Rome 500 years later tell us quite a bit about the society of the day.
These four [Matthew, Mark, Luke and John] were to write it down with their own fingers; there were to compose, sing and proclaim what they had seen and heard of Christ's powerful strength - all the many wonderful things, in word and deed, that the mighty Chieftain Himself said, taught, an accomplished among human beings - and also all the things which the Ruler spoke from the beginning, when He, by His own power, first made the world and formed the whole universe with one word.
First, the power of God comes from the word of God - 'God's spell' or gospel. Holy magic comes from divine incantation, and all of the universe is formed from God's words.
Rumuburg or Rome is made the centre of the imperial warrior-religion that would follow Christ by God's will, even though Christ was to be born among his 'warrior-companions' in Israel. Christ was born under the authority of a Roman emperor and his power and authority would transfer to Rome and Roman emperors and popes thereafter.
Geld, the Germanic word for worth or tribute payment, is used for worship - quite literally 'worth-ship' - which makes sense at a time when all sins could be redeemed for payment to ensure divine favour after death. An offering of geld measured your devotion and your worth to an earthly king as taxes and geld also measured your heavenly worth to God's church. Ritual observance mattered too, but in a pinch gold and silver would do just fine.
Unflinching loyalty to a chieftain, especially in battle, is the highest virtue, as is loyalty to God. Loyalty to a chieftain, whether the divine Christ or a more earthly king, measured worthiness as a warrior-companion of Jesus. Remember that at this time all Kings were consecrated as the instruments of God's will on earth, and within a century Christian warriors would go on crusade against heretics and tyrants as God's enemies.
When Zachary, made a nobleman-priest in the Heliand, is approached to confirm the name of the infant delivered to his aged wife he is given a beech stave to incise the name on, uuritan gives us the English word writing. The power of the inscribed name John confirms the infant John's power as an evangelist and restores Zachary's speech.
Joseph and Mary are from noble families and Joseph is a warrior chieftain among the Nazarenes as a humble carpenter just wouldn't do. In 9th century Germanic society only warriors were law-worthy and owed the protection of their chieftains for their service. The Roman Church had likewise adapted to a very mercantile sort of evangelism. Rome wanted protection from Goths and Sarcens, trade, gold and silver for its church, so it targeted chieftains and warriors and mercantile elites as converts. The weak and poor were of no interest then or for centuries afterwards.
Just as 'clear-thinking' loyalty is the highest virtue of men, Mary is depicted as 'clear-thinking' and trusting when informed she is to bear Christ by the Holy Spirit. "Let it be done unto me according to your words, whatever my Lord wills - nor is my mind in doubt, neither in word nor in deed. And so I have heard it told that the woman very gladly received the message of God with an easy mind, with good faith and with transparent loyalty. The Holy Spirit became the baby in her womb." The Trinity has always been a controversial doctrine, but in the Heliand the Holy Spirit morphs into the embryonic Jesus Christ.
The census in the Heliand requires warriors to return to the hill-fort burgs of the clan where they were born. (This makes no less sense than the Biblical version. If Mary and Joseph were both descended from King David, then so were all their families, and they would have travelled in a massive family party to Jerusalem.) Virtually all mercantile and maritime tribes of the north lived in secure hill-fort cantons and practiced fostering of their young, sending boys away at age 7 or so to be fostered to adulthood elsewhere, negotiating fostering as carefully as marriages. Fostering promoted like-minded fellowship, education, alliances, trade networks, suitable marriages, survival from local attacks, and ensured young were raised to be multi-lingual, productive and disciplined - rather like upper classes sending their young to public boarding schools at age 7 now. A Celtic audience would understand that warriors were being told to return to census counts in their birth burgs. In that sense, it makes more sense than the biblical version.
The birth in a stable story is omitted. No divine warrior of God could begin life so low. The birth is announced by God's angel as being at Bethlemhemburg, within the walls, as befits a warrior chieftain, and the magic of Christ's birth is confirmed by the heavenly angels' songs: "They then began to sing a holy song as they wended their way through the clouds towards the meadows of heaven."
Where the Roman bible has shepherds and sheep, the Heliand has Christ's birth witnessed by horse grooms guarding horses. Among the warrior class of the 9th century any contact with chattel animals belonged to the class of slaves or serfs that worked the land and tended the herds. Only horses were noble and served the warrior class.
We'll stop there. By now you get the point.
Christianity has always reinvented itself to adapt to local tastes and biases. Because we are familiar with the bible story, the Heliand provides valuable contrasts and inconsistencies that illuminate the 9th century warriors it was written to entertain and convert.