A mumin is expected to have both hope and fear in regards to Allah's mercy and punishment. Imam Sadiq (as) quotes from Luqman's advices that if we cut a mumin's heart in to two equal pieces, you will see half is full of hope and the other half full of fear. (Al-Kafi, chapter of fear and hope, Hadith No.1)
We recite Bimillah several times a day in which we attribute Allah swt to be Rahman and Rahim, All compassionate and All merciful. From such a God, there is no need to have the feeling of threat. He can't be schemer of a bad plan for his own servants as long as they are mumineen.
Yes, a person can have such a feeling that Allah swt would scheme a bad plan when he knows his own short comings in terms of servitude. At this time, a person is not safe.
But on the same side, Allah swt has asked us to repent and do proper tawbah and He is definitely going to accept it. The biggest sin is to be hopeless of Allah's mercy!
So practically there is no room of being threatened by Allah's scheme as long as person does tawbah after a particular sin.
This verse applies to those who think that they can go on committing sins and Allah swt is just a mere watcher and He is not going to punish the wrong doers.