All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Our advice to you regarding whispers is to repel them, ignore them and not give any attention to them.
As regards steadfastness in worship, then you must strive against your own evil self and perform little deeds, because you are able to persevere on that and gradually increase. You also have to keep company with the righteous people, strive to learn Islamic knowledge, and mention Allah as much as possible and supplicate Him; all these acts will help you, Allah willing, to be steadfast on obedience.
For more benefit on whispers, please refer to Fatawa 374308 and 356689.
For more benefit on how to increase one’s Imaan and be steadfast on doing good deeds, please refer to Fatwa 428923.
Allah knows best.