Who was the old man at the beginning of The Force Awakens?

Question

Who was the old man at the beginning of the movie?

The one that was with Poe. By what he says he seems a relevant character to me, the way he talks about the Jedi.

P.S. I don't believe I spoil anything with this question

Answer 1

He deliberately was vague, but we get the feeling from Alan Dean Foster's novelization of The Force Awakens that there's a deep back-story behind Lor San Tekka, and likely one that will be told by Disney in the future:

First, a physical description hinting at great strength:

While Lor San Tekka appeared physically capable of removing the heads from various unthinking carnivores, his manner was more that of a Soother, and a professional one at that. One immediately relaxed in his company. Provided one held no inimical intentions toward the hut’s owner, of course.

Then, we get a hint that he feels the need to atone for something in his past, and has a conscience:

“These days I can only do so much. Would that I could do so much more.” He sighed heavily. “And there is so much more that needs to be done. But…this will begin to make things right.”

Then, we see that he's supposed to have a deep and interesting history:

“Legend says this map is unobtainable,” Poe noted. “How’d you do it?” The older man just smiled, clearly not willing to give up all his secrets just yet.
Poe grinned back at him, accepting it. “I’ve heard stories about your adventures since I was a kid. It’s an honor to meet you. We’re grateful.”
Tekka shrugged—an old man’s shrug, slow and full of meaning. “I’ve traveled too far and seen too much to ignore the collective anguish that threatens to drown the galaxy in a flood of dark despair. Something must be done; whatever the cost, whatever the danger. Without the Jedi, there can be no balance in the Force, and all will be given over to the dark side.”
Though Poe was reasonably secure in his knowledge of such things, he was also intelligent enough to know he could not begin to discuss them in depth with someone like Lor San Tekka.

He also seems to have some backstory with Leia Organa:

“The general has been after this a long time,” Poe said, as a way of beginning to take his leave.
Tekka smiled at some secret thought. “ ‘General.’ To me, she’s royalty.”

And he is responsible for village's defense...

“If you wish to flatter something, flatter my memory. Go. Now! I must see to the defense of the village.” Turning, Tekka headed off, not looking back.

... because he's a village elder. And, he knows Kylo Ren and Stimpy from his past as a mercenary.

Seeing him approach, Tekka halted and waited: The village elder recognized who was coming toward him and knew there was no point in running. Resignation slid over him like a cloud.

Tekka gazed back evenly. The black mask, with its slitted forehead and thick, snoutlike breathing apparatus, covered the face of the man he knew as Kylo Ren. Once, he had known the face behind the mask. Once, he had known the man himself. Now, to San Tekka, only the mask was left. Metal instead of man.
Ren spoke first, without hesitation, as if he had anticipated this meeting for some time. “The great soldier of fortune. Captured at last.” Though emanating from a human throat, the voice that was distorted by the mask had the sick flavor of the disembodied.

---

Additional information is available in SW Databank

A legendary traveler and explorer, Lor San Tekka is a longtime ally of the New Republic and the Resistance. After the Battle of Endor, San Tekka helped Luke Skywalker recover secret Jedi lore that the Empire had tried to eras...
he follows the dictates of the once-forbidden Church of the Force.

His religious identity seems important, since his initial production moniker was "The Vicar".

---

UPDATE:

According to TFA Visual Dictionary:

• He's a seasoned traveler, adventurer and explorer, who provided maps and info to New Republic and Resistance

• Always disbelieved Palpatine's version of Jedi's betrayal

• Knows Jedi secrets from his travels

• NOT Force sensitive

• Follower of Church of the Force

Answer 2

I believe you're talking about:

Lor San Tekka. Doesn't seem to be much info on him (understandably), apart from he's an elder of a village on Jakku, a desert planet in a remote section of the Western Reaches (they're always in a remote section!).