Word by Word Analysis

لَوْ كَانَ عَرَضًا قَرِيبًا وَسَفَرًا قَاصِدًا لَّٱتَّبَعُوكَ وَلَـٰكِنۢ بَعُدَتْ عَلَيْهِمُ ٱلشُّقَّةُ ۚ وَسَيَحْلِفُونَ بِٱللَّهِ لَوِ ٱسْتَطَعْنَا لَخَرَجْنَا مَعَكُمْ يُهْلِكُونَ أَنفُسَهُمْ وَٱللَّهُ يَعْلَمُ إِنَّهُمْ لَكَـٰذِبُونَ 42

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