Sustainable development is the theme of human social development in the 21st century, and the Sustainable Development Goals (SDGs) outlined in Agenda 2030 have become global development goals. Education plays a fundamental role in progressing SDGs, and sustainable development education is the key to attaining sustainable development [1]. Sustainable development education aims to ensure inclusive and equitable quality education. As participants and facilitators of sustainable development education, teachers carry great challenges as they not only deal with challenging students and parents but also handle heavy teaching and administrative tasks daily [2]. As a result, teachers are at a high risk of burnout [3].

A study by Wu et al. ^[4][5] found that burnout in elementary and secondary school teachers in China has not been alleviated, but become more severe than a decade ago. Teacher burnout not only adversely affects teachers’ psychological health ^[5][6], but may also affect their support and commitment to sustainable development education in the 21st century ^[6][7]. Teachers can only achieve sustainability if they manage their burnout to the extent that they can self−regulate it ^[7][8]. Therefore, exploring the causes and solutions of burnout in elementary and secondary school teachers has become a common concern in Chinese society. Domestic and international studies have shown that teacher burnout is influenced by both internal and external factors ^[8][9]. Internal individual factors include gender, personality, beliefs, age, marital status, well−being, emotional intelligence, etc.; external organizational environment factors include teachers’ economic income, career advancement opportunities, organizational climate, etc. ^[9][10]. In recent years, as research on this issue has intensified, scholars have turned to the perspective of leadership styles. Studies have shown that transformational leadership ^[10][11][11,12], principal instructional leadership ^[12][13], integrity leadership ^[13][14], and emotional leadership ^[14][15] are all negatively related to teacher burnout. Spiritual leadership, as a new leadership style, may also be an important external environmental factor in alleviating teacher burnout. Spiritual leadership, as a new leadership model that focuses on intrinsic motivation, pays more attention to the spiritual dimension of employees at work. Leaders influence and lead members to develop a sense of spiritual presence by establishing spiritual−level attitudes and behaviors to achieve organizational goals ^[15][16]. Research has shown that spiritual leadership can reduce burnout among corporate employees ^[16][17] and healthcare workers ^[17][18] who were chosen as the participants. However, in the field of education, there is little literature on the relationship between spiritual leadership and teacher burnout, which warrants further in−depth exploration. Career calling is a powerful, meaningful, and positive emotion that an individual experiences while performing a job. Studies revealed that career calling significantly predicted teacher burnout ^[18][19]. As a personal trait, emotional intelligence is an important factor in maintaining teachers’ physical and mental health. Fiorilli et al. ^[19][20] and Ding et al. ^[20][21] revealed that teachers’ emotional intelligence significantly negatively predicts teacher burnout. Therefore, spiritual leadership is likely to affect elementary and secondary school teacher burnout through career calling and emotional intelligence.

2. Spiritual Leadership and Teacher Burnout

Fry ^[15][16] proposed a causal model of spiritual leadership theory on the basis of the intrinsic motivation model. This causal model emphasizes that the goal of spiritual leadership is to satisfy the needs of followers for spiritual survival by calling and membership, create a shared vision and value of individuals, teams, and organizations, and ultimately promote higher levels of organizational outcomes. Therefore, spiritual leadership is a behavioral approach to leadership effectiveness that intrinsically motivates and satisfies subordinates based on the spiritual presence of a sense of calling and identity, and consists of three dimensions: vision, hope/faith, and altruistic love ^[21][22]. According to related literature, spiritual leadership has a positive and significant influence on individual spiritual well−being ^[22][23], job satisfaction ^[23][24], innovative behavior ^[24][25], organizational citizenship behavior ^[25][26], organizational commitment and performance ^[26][27], and organizational trust ^[27][28]. Recent studies have shown that spiritual leadership can reduce job burnout ^[16][17][17,18] and deviant behavior at work ^[28][29]. Spiritual leadership enhances workplace spirituality, positively predicts employee well−being ^[29][30], and mitigates burnout ^[30][31] by portraying an organizational vision that makes employees feel meaningful and valuable at work, giving them hope and faith, and altruistic love ^[17][18]. In the education field scenario, a principal’s spiritual leadership enhances teachers’ sense of career calling and values by planning a school development vision for teachers; builds confidence and hope for teachers so that they can have more courage and perseverance to overcome difficulties and setbacks at work; and, coupled with the altruistic love given to teachers to enable them to feel the warmth and strength of the collective, enhances teachers’ job satisfaction and enthusiasm and mitigates teacher burnout.

3. Spiritual Leadership, Career Calling, and Teacher Burnout

Career calling may provide an intermediary between spiritual leadership and teacher burnout. Career calling is a positive psychological state in which individuals integrate their work with personal and social meaning, hope their work to be valuable to society, and experience intrinsic pleasure and self−fulfillment in their careers ^[31][32]. In modern society, no organization can function well without being driven by its calling, especially in public schools that are not profit−oriented. Employees who are motivated by their calling and initial intention in an organization are more likely to align organizational expectations with self−expectations in the process of career development and self−growth and are more likely to find meaning and value in their lives and work. According to empirical research, spiritual leadership has a significant positive effect on the career calling of public sector employees, and nurses ^[32][33][33,34]. Chang et al. ^[34][35] also found this causal relationship in a survey of 333 participants across industries. According to spiritual leadership theory, spiritual leadership, as an external situational factor, motivates individuals with intrinsic motivation, such as career calling, which drives individuals to dedicate themselves to their work, achieve self−worth, and experience inner joy ^[17][18]. Also, career calling is considered a protective factor against burnout. Liao et al. ^[35][36] found that people with a higher career calling had a clearer self−concept at work, felt relatively less stress, were less likely to be in a depressed mood, and had better coping strategies for professional challenges. Studies have demonstrated that career calling negatively and significantly affects teacher burnout ^[10][18][36][11,19,37].

4. Spiritual Leadership, Emotional Intelligence, and Teacher Burnout

Emotional intelligence may be a mediating variable between spiritual leadership and teacher burnout. An individual’s ability to evaluate, express, manage, and utilize his or her own and others’ emotions is called emotional intelligence, which consists of four dimensions: self emotional appraisal, others’ emotional appraisal, use of emotion, and regulation of emotion ^[37][38]. Although emotional intelligence depends on individual demographic factors and personality traits to some extent ^[38][39], research has shown that organizational contextual factors, such as leadership behaviors, can also influence employees’ emotional intelligence ^[39][40]. Studies have shown that inclusive leadership by elementary school principals significantly and positively correlates with teachers’ emotional intelligence ^[40][41] and transformational leadership of hotel managers has a significantly positive effect on employees’ emotional intelligence ^[41][42]. Spiritual leadership, as a type of leadership behavior, may also be able to provide good preconditions for teachers to better identify and navigate their own and others’ emotions through behaviors such as visionary motivation, trust, and selfless care. The principal’s spiritual leadership behavior allows teachers to feel the principal’s support and trust in their work, which satisfies their psychological needs and leads to positive emotional experiences. Positive teacher emotions better enable teachers to recognize and understand their own and others’ emotions, to be good at controlling their own emotions, and to be able to transform their positive emotions into motivation and the ability to behave. Therefore, principals’ spiritual leadership can improve teachers’ emotional intelligence. Also, research has shown that emotional intelligence is an important factor in maintaining teachers’ physical and mental health and that teachers’ emotional intelligence significantly and negatively predicts teacher burnout ^[42][43][44][43,44,45]. Teachers with good emotional intelligence are able to adaptively regulate their emotions, attitudes, and behaviors to avoid burnout symptoms when they are exposed to external work stress. In summary, spiritual leadership may indirectly predict teacher burnout through the mediating roles of career calling and emotional intelligence. Self−determination theory is a motivational process theory about individuals’ self−determined behaviors proposed by Deci and Ryan. The theory suggests that the social environment can boost an individual’s internal motivation by meeting basic psychological needs and facilitating the internalization of external motivation, which in turn influences individuals’ behavioral choices ^[45][46].