(And Allah knows better.
(And Allah knows better.) “but this (only) increased their faith”: It is but natural that when a man intends to do something, and someone whom he does not trust - advises him not to do it, then that prohibition gives an impetus to do it by all means; his powers and faculties become geared to do that work, and his intention becomes firmer. The more the said advisor persists in prohibition, the more determined the man becomes to do it.
This effect is even more stronger when the man so advised believes that he is on right and that he must do what his duty requires him to do. That is why whenever someone blamed the believers regarding some divine orders or put hindrance in their way, their belief increased even more and their determination and courage became much more stronger.
Possibly one factor that helped to increase their faith was the confirmation that such news produced of the revealed information that they had had in advance that they would have to suffer trouble, harm and damage in the divine cause until their affairs were favorably settled by Allah’s permission. Allah had promised to help them, and naturally that type of help presupposes fighting and war.
“and they said: ‘Allah is sufficient for us and most excellent Protector is (He)’ “: 'hasbuna (sufficient for us); this word is derived from al-hisab (to count, to reckon), because sufficiency is reckoned, vis-à-vis, the need. The sentence portrays their total dependence on Allah, because of their faith - without caring, about external causes, which the divine system has created in the world. al-Wakil (= agent, manager, representative) refers to one who manages the affairs on behalf of someone.
The connotation of the verse is therefore similar to that of the verse 65:3: and whoever trusts in Allah, He is sufficient for him; surely Allah attains His purpose.
That is why this clause (and they said: “Allah is sufficient for us and most excellent Protector is (He) “) has been followed by the words, “So they returned with favor from Allah and (His) grace; no evil touched them.” Therefore, when they followed His pleasure, He praised them in these words, “and they followed the pleasure of Allah; and Allah is the Lord of mighty grace”.
TRUST IN ALLAH The fact is that fulfillment of desire and success of design in this material world depends on some material and other psychological causes.