Although it is highly desirable that all members of the National Assembly attend every meeting of the Assembly, the fact that a member is prevented by business or other circumstances from having a good attendance record is not a ground upon which a resignation can be accepted. It is not justified to accept a resignation or otherwise declare a vacancy on the National Assembly without a valid reason such as in the case of prolonged absence or serious illness which prevents one from discharging his duties as a member of the National Assembly.
(Universal House of Justice, Lights of Guidance, p. 49)
As regards the question of what procedure the Bahá’í Assemblies should adopt when dissatisfied with the services of any of their officers, should such dissatisfaction involve the loyalty of an Assembly officer to the Faith, he should, following a majority vote, be dismissed. But in case the dissatisfaction is due to the incompetence of a member, or simply to a neglect on his part to discharge his duties, this does not constitute sufficient justification to force his resignation or dismissal from the Assembly. He should be kept in office until new elections are held.
(Shoghi Effendi, Principles of Bahá’í Administration, p. 50)
As you know the beloved Guardian highly reprobated resignation from any office to which a believer has been elected and it is certainly best, at this present state of the Cause, for the friends to accept elective service whenever they are called upon to do so. However, there is no objection for an overburdened believer asking the Spiritual Assembly to which he may be elected not to appoint him as an officer or to a committee.
(Universal House of Justice, 9 December 1970, to a National Spiritual Assembly)
Concerning the question of refusal by certain believers to accept election to an administrative post: The Guardian strongly feels that criticism, opposition, or confusion do not provide sufficient grounds for either refusal or resignation. Only cases of physical or mental incapacity, which, by their very nature, are extremely rare, constitute valid reasons for such an act. The difficulties and tests involved in the acceptance of administrative posts, far from inducing the believers to dissociate themselves from the work of the Cause, should spur them on to greater exertions and to a more active participation in the privileged task of resolving the problems that confront the Bahá’í community… . The believers, for the sake of the Cause, now in the period of its infancy, should accept their duties in a spirit of self-sacrifice, and should be animated by the desire to uphold the verdict of the electorate, and to lend their share of assistance, however difficult the circumstances, to the effective administration of the affairs of the Faith.
(Shoghi Effendi, NSA USA - Developing Distinctive Bahá’í Communities)
Needless to say how much he was afflicted to learn that you both had offered your resignation from the ... Spiritual Assembly. For he is convinced that your action in this matter will have a bad effect on the rest of the believers, and in this way cause great injury to the Cause. Differences of opinion, specially when they arise in connection with personalities, should under no circumstances lead any believer to turn his attention from his major Bahá’í activities. And what activity can be said to be more vital, and hence of a more weighty responsibility than to serve in an Assembly, and specially in the capacity of a Vice-Chairman. Your responsibilities, in this connection, are indeed manifold, and it would be a pity, therefore, if you fail in the least to carry them out to the fullest possible extent. Besides, you can easily realize that by resigning from the Assembly you would be encouraging, quite unintentionally but though the mere effect of example, your fellow-members to take a similar action in the future if necessary. This, of course, cannot be lead eventually to the disruption of your Assembly, and would in the meantime greatly detract from the authority and prestige for that body in the eyes of the public.
(Shoghi Effendi, Lights of Guidance, p. 48)
Personal differences and disagreements among Assembly members surely afford no sufficient ground for such resignation, and certainly cannot justify absence from Assembly meetings. Through the clash of personal opinions, as ‘Abdu’l-Bahá has stated, the spark of truth is often ignited, and divine guidance revealed.
(Shoghi Effendi, The Local Spiritual Assembly, p. 21)
The National Spiritual Assembly cannot refuse accepting a resignation when it is well justified, and when it is done not with the purpose of shirking responsibility… .
(Shoghi Effendi, Dawn of a New Day, p. 49)
The remedy to Assembly inharmony cannot be in the resignation or abstinence of any of its members. It must learn, in spite of disturbing elements, to continue to function as a whole, otherwise the whole system would become discredited through the introduction of exceptions to the rule.
(Shoghi Effendi, The Local Spiritual Assembly, p. 21)
Those who have been elected to such membership should consider it a privilege and also a responsibility to serve in that body, and should therefore refrain from any resignation, even though they may disagree with the majority of the members. Obedience to the considered views and policies of the majority should by whole hearted, for it implies obedience and loyalty to the Administrative Order itself.
(Shoghi Effendi, Lights of Guidance, p. 32)
With reference to your question whether it would be permissible for a believer to resign from the Local Assembly; under special circumstances, such as illness, one may do so, but only after, and never before he has been elected to the membership of the Assembly.
(Shoghi Effendi, in The Local Spiritual Assembly, p. 21)