Read Ruku 161 of the Quran

ٱنفِرُوا۟ خِفَافًۭا وَثِقَالًۭا وَجَـٰهِدُوا۟ بِأَمْوَٰلِكُمْ وَأَنفُسِكُمْ فِى سَبِيلِ ٱللَّهِ ۚ ذَٰلِكُمْ خَيْرٌۭ لَّكُمْ إِن كُنتُمْ تَعْلَمُونَ ﴿٤١﴾

Go forth, whether light or heavy, and strive with your wealth and your lives in the cause of Allah. That is better for you, if you only knew.

لَوْ كَانَ عَرَضًۭا قَرِيبًۭا وَسَفَرًۭا قَاصِدًۭا لَّٱتَّبَعُوكَ وَلَـٰكِنۢ بَعُدَتْ عَلَيْهِمُ ٱلشُّقَّةُ ۚ وَسَيَحْلِفُونَ بِٱللَّهِ لَوِ ٱسْتَطَعْنَا لَخَرَجْنَا مَعَكُمْ يُهْلِكُونَ أَنفُسَهُمْ وَٱللَّهُ يَعْلَمُ إِنَّهُمْ لَكَـٰذِبُونَ ﴿٤٢﴾

Had it been an easy gain and a moderate trip, the hypocrites would have followed you, but distant to them was the journey. And they will swear by Allah, "If we were able, we would have gone forth with you," destroying themselves [through false oaths], and Allah knows that indeed they are liars.