Surah At-Tawbah: Chapter 9 (line 90-100) the Repentance

90. Some of the Desert-Arabs came to make excuses, asking to be granted exemption, while those who were untrue to God and His Messenger stayed behind. A painful punishment will afflict those among them who disbelieved.

91. There is no blame on the weak, nor on the sick, nor on those who have nothing to give, provided they are true to God and His Messenger. In no way can the righteous be blamed. God is Forgiving and Merciful.

92. Nor on those who approach you, wishing to ride with you, and you said, “I have nothing to carry you on.” So they went away, with their eyes overflowing with tears, sorrowing for not finding the means to spend.

93. But blame is on those who ask you for exemption, although they are rich. They are content to be with those who stay behind. God has sealed their hearts, so they do not know.

94. They present excuses to you when you return to them. Say, “Do not offer excuses; we do not trust you; God has informed us of you. And God will watch your actions, and so will the Messenger; then you will be returned to the Knower of the Invisible and the Visible, and He will inform you of what you used to do.”

95. They will swear to you by God, when you return to them, that you may leave them alone. So leave them alone. They are a disgrace, and their destiny is Hell; a reward for what they used to earn.

96. They will swear to you that you may accept them. But even if you accept them, God does not accept the wicked people.

97. The Desert-Arabs are the most steeped in disbelief and hypocrisy, and the most likely to ignore the limits that God revealed to His Messenger. God is Knowing and Wise.

98. And among the Desert-Arabs are those who consider their contribution to be a fine. And they wait for a reversal of your fortunes. Upon them will fall the cycle of misfortune. God is Hearing and Knowing.

99. Yet among the Desert-Arabs are those who believe in God and the Last Day, and consider their contribution to be a means towards God, and the prayers of the Messenger. Surely it will draw them closer, and God will admit them into His mercy. God is Forgiving and Compassionate.

100. The Pioneers-The first of the Migrants and the Supporters, and those who followed them in righteousness. God is pleased with them, and they are pleased with Him. He has prepared for them Gardens beneath which rivers flow, where they will abide forever. That is the sublime triumph.

My interpretation: 

Gabriel is also explaining to Muhammad that God sees all, and those who are too sick, weak, and physically unable to fight with Muhammad, God sees this. They are in no way punished. God is fair and just and only punishes those who could have done more, but chose not to.

There were people who wanted to ride with Muhammad and his small army, but they had no horse or camel, and Gabriel is telling him that these people who went away with tears in their eyes were seen by God. They had good intentions and God saw this.

Among the desert Arabs are the ones that have not been believers of Muhammad so they are not considered muslims and when asked to donate to those in need, they see it like a fine or a tax, instead of welcoming it from their own hearts. They stay with their wealth and homes, and lead a life of inaction. God sees them too.

And among the desert Arabs are those who welcome Muhammad’s messages and gladly give to fill their hearts with happiness that they have helped others. These are the ones that God and the Angels see as being good and will be in paradise in the end.