563. Commandment – O ye who believe! when you go forth in the cause of Allah, make proper investigation and say not to anyone who greets you with the greeting of peace, ‘Thou art not a believer.’

[4:95] O ye who believe! when you go forth in the cause of Allah, make proper investigation and say not to anyone who greets you with the greeting of peace, ‘Thou art not a believer.’ You seek the goods of this life, but with Allah are good things in plenty. Such were you before this, but Allah conferred His special favour on you; so do make proper investigation. Surely, Allah is well aware of what you do.