﴿ ٱنفِرُوا۟ خِفَافًۭا وَثِقَالًۭا وَجَٰهِدُوا۟ بِأَمْوَٰلِكُمْ وَأَنفُسِكُمْ فِى سَبِيلِ ٱللَّهِ ۚ ذَٰلِكُمْ خَيْرٌۭ لَّكُمْ إِن كُنتُمْ تَعْلَمُونَ ﴾

“Go forth to war, whether it be easy or difficult [for you], and strive hard in God's cause with your possessions and your lives: this is for your own good -if you but knew it!”

In the fourth verse (41), the command given earlier has been repeated for emphasis. It is being said here that, once the Prophet of Allah orders people to come out for Jihad, they must come out as a matter of absolute obligation - for on the compliance of this command hinges all that is good for them.