Back 
Surah 9. Al-Tawba
Ayah 42
42 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 gain and an easy journey, they would have followed you, but the distance was long for them; and they would swear by Allah: "If we only could, we would certainly have come forth with you.'' They destroy themselves, and Allah knows that they are liars.
Allah admonishes those who lagged behind and did not join the Prophet for the battle of Tabuk, those who asked the Prophet for permission to remain behind, falsely pretending to have legitimate reasons to do so,
(Had it been a near gain), booty right in front of them, according to Ibn `Abbas,
(and an easy journey), travel for only a short distance,
(they would have followed you.) But,
(the distance was long for them), to Ash-Sham,
(and they would swear by Allah), when you return to them,
(If we only could, we would certainly have come forth with you), had not there been a valid excuse, we would have gone out with you,
(They destroy themselves, and Allah knows that they are liars.)