وَتَوَكَّلْ عَلَى ٱللَّهِ ۚ وَكَفَىٰ بِٱللَّهِ وَكِيلًا
Wa tawakkal 'alal laah; wa kafaa billaahi Wakeelaa
Put your trust in God: God is enough to trust.
And put your trust in God — God is enough as a guardian of affairs.
Placement carries the weight here: the surah has just told the Prophet to hold his ground against pressure from two directions, and within two verses it will overturn a settled Arabian custom about adopted sons, an instruction that would cost him socially. Wakil belongs to the language of agency, the one you hand your affairs to, who then acts in your name, and the trust is issued as equipment, ahead of the hard part.