Tafsir of At-Tawbah 9:45

إنما يستٲذنك

and Allah is the All-Knower of those who have Taqwa. Those who ask your leave, to remain behind, without a valid excuse,

الذين ﻻ يومنون بالله واليوم اﻻخر

those who believe not in Allah and the Last Day, they do not hope for Allah's reward in the Hereafter for their good actions,

وارتابت قلوبهم

and whose hearts are in doubt, about the validity of what you brought them,

فهم في ريبهم يترددون

so in their doubts they waver. They waver in doubt, taking one step forward and one step back. They do not have a firm stance in anything, for they are unsure and destroyed, neither belonging to these nor to those. Verily, those whom Allah misguides, will never find a way for themselves to guidance