﴿ ۞ وَلَوْ أَرَادُوا۟ ٱلْخُرُوجَ لَأَعَدُّوا۟ لَهُۥ عُدَّةًۭ وَلَٰكِن كَرِهَ ٱللَّهُ ٱنۢبِعَاثَهُمْ فَثَبَّطَهُمْ وَقِيلَ ٱقْعُدُوا۟ مَعَ ٱلْقَٰعِدِينَ ﴾

“For, had they been [truly] desirous of setting out [with thee], they would surely have made some preparation therefor: but God was averse to their taking the field, and so He caused them to hold back when it was said, "[You may] stay at home with all [the others] who stay at home."”

If they had desired to go forth with you they would have made some preparation for it some equipment such as tools and provisions but God was averse that they should be sent forth that is He did not want them to go forth so He slowed them down He made them feel lethargic and it was said to them ‘Stay back with those who stay back!’ with the sick the women and the children in other words God decreed this.