Is the analysis of a man marrying a second, third, or fourth wife without reason, even if his first wife is fulfilling all her duties, considered mercy and compassion and does it observe justice between the spouses?

Allah has permitted a man to marry more than one wife—up to four women—if he is able to fulfill the duties of polygyny and maintain justice among his wives. A believer must submit to Allah's ruling in this regard without objection or hesitation.