Hex.38.5 His ancestor bites through skin

Who is the ancestor?

I always wondered what the ancestor meant. I found this:
The ancestor can be a leader, grandfather, a person of authority in a family, husbandanyone who has the position to exercise some control. 
This is China long ago, feel free to change it to the female version if that fits better.

宀 示
The character consists of 'roof' and 'altar'. It refers to a certain type of thing or person that has a leading role or is the first: sovereign, leader, eldest son, respect, fundamental, ancient emperor temple, an ancient ritual, official title, take charge of the ritual of sacrifice. I think it is a picture of the little altar in a house where the family honors their grandfather/mother and so on.

The fanyao (corresponding line of the relating hexagram)

38.5 Regrets go away. The clan leader bites through skin. Proceed, how can it be faulty.
Trigram Fire turns into Heaven. Controlling but not too much (just skin, not through hard bone or so).

10.5 Decisive treading. Determination: danger.
Trigram Heaven turns into Fire. Decisive but not too much.

38.5 changes into 10.5 if it is 'old yin', 10.5 changes into 38.5 if it is 'old yang': they are each other's fanyao.

What does it mean in an answer?

If one of the two is too strong, they will clash. If it is the one in authority (or thinks he/she is) it will be 'faulty'. If it is the one of 10.5: being decisive is good, but it always involves risk; how much depends on its flexibility.

Hex.3.3 "The noble one knows the seeds"

In hexagram 3 line 3 is the character ji, which is intriguing. It can be translated as "seed", the very first beginning of something, when it is not yet really visible. 

幺 戍
It is composed of 幺 (small, doubled) and 戍 (frontier guard). From Wieger: Frontier guards “are attentive to the least movement, to the smallest event".
幺 is actually a picture of silk - very slight, thin, hardly visible.

There are more lines with this character, but all of them about the moon being 'almost' full. On the verge of being full, but just not yet. It is a moment when things can change. A full moon is a time of 'much', but being on the verge of full is a meaningful but still rather undefined moment. See 9 line 6, 54 line 5 and 61 line 6.

There is another character with the meaning 'full', which simply tells us that the moon is 'round', a symbol of success or the kind of mind which can reach success. But the character 'full' in these three lines also means 'hope', prestige and it is also the name of an ancient sacrifice, or to offer a sacrifice to the dead whose remains are buried far away and to mountains and rivers, sun, moon and stars.