This study examined the longitudinal relationships between job resources, personal resources, and work engagement. Based on the Conservation of Resources (COR) theory, the researchers hypothesized that these three factors are reciprocally related over time. The study involved 163 employees followed over 18 months. Structural equation modeling supported the hypotheses, showing that job and personal resources at Time 1 positively related to work engagement at Time 2, and that work engagement at Time 1 positively related to job and personal resources at Time 2. The best-fitting model was the reciprocal model, indicating that job and personal resources, as well as work engagement, are mutually related. These findings support the COR theory that various resources and well-being form a cycle influencing employees' adaptation to their work environments. The study focused on job resources (e.g., autonomy, social support, coaching, feedback, professional development) and personal resources (self-efficacy, organizational-based self-esteem, optimism). Job resources help achieve work goals, reduce job demands, and stimulate personal growth. Personal resources are positive self-evaluations linked to resilience and the ability to control one's environment. Both job and personal resources contribute to work engagement, which is characterized by vigor, dedication, and absorption. The study found that job and personal resources at Time 1 positively predicted work engagement at Time 2, and that work engagement at Time 1 positively predicted job and personal resources at Time 2. Additionally, job and personal resources were reciprocally related. These findings support the idea that resources and well-being form a cycle, with each factor influencing the others. The study also controlled for potential selection bias and found no significant differences between participants and dropouts. The results suggest that job and personal resources are equally important in explaining work engagement, and that work engagement can lead to the mobilization of job and personal resources. The findings have implications for organizational practices, emphasizing the importance of creating resourceful work environments and training programs that enhance employees' positive self-beliefs.This study examined the longitudinal relationships between job resources, personal resources, and work engagement. Based on the Conservation of Resources (COR) theory, the researchers hypothesized that these three factors are reciprocally related over time. The study involved 163 employees followed over 18 months. Structural equation modeling supported the hypotheses, showing that job and personal resources at Time 1 positively related to work engagement at Time 2, and that work engagement at Time 1 positively related to job and personal resources at Time 2. The best-fitting model was the reciprocal model, indicating that job and personal resources, as well as work engagement, are mutually related. These findings support the COR theory that various resources and well-being form a cycle influencing employees' adaptation to their work environments. The study focused on job resources (e.g., autonomy, social support, coaching, feedback, professional development) and personal resources (self-efficacy, organizational-based self-esteem, optimism). Job resources help achieve work goals, reduce job demands, and stimulate personal growth. Personal resources are positive self-evaluations linked to resilience and the ability to control one's environment. Both job and personal resources contribute to work engagement, which is characterized by vigor, dedication, and absorption. The study found that job and personal resources at Time 1 positively predicted work engagement at Time 2, and that work engagement at Time 1 positively predicted job and personal resources at Time 2. Additionally, job and personal resources were reciprocally related. These findings support the idea that resources and well-being form a cycle, with each factor influencing the others. The study also controlled for potential selection bias and found no significant differences between participants and dropouts. The results suggest that job and personal resources are equally important in explaining work engagement, and that work engagement can lead to the mobilization of job and personal resources. The findings have implications for organizational practices, emphasizing the importance of creating resourceful work environments and training programs that enhance employees' positive self-beliefs.