Missing DL = Mortal Sin?

[Dave_in_Dallas]

In the RCC if one is to miss Mass (assuming for no good reason) then we fall into a state of grave/mortal sin. The we’re out of a state of grace and heading toward hell.
Is there a similar such doctrine in the EC/EO?

 

[Vico]

In the RCC if one is to miss Mass (assuming for no good reason) then we fall into a state of grave/mortal sin. The we’re out of a state of grace and heading toward hell.
Is there a similar such doctrine in the EC/EO?

Certainly the second commandment is to be taken seriously. From one Byzantine Catholic Church, Examination of Conscience document:

r-fol.com/st.athanasius/
stmichaelbyz.org/resources/

Remember to keep holy the Lord’s day.
Have I deliberately missed Liturgy on Sundays or Holy Days of Obligation?
Have I tried to observe Sunday as a family day and a day of rest?
Do I do needless work on Sunday?