Adam Clarke on Matthew 10:26

Fear them not - A general direction to all the persecuted followers of Christ. Fear them not, for they can make you suffer nothing worse than they have made Christ suffer; and under all trials he has promised the most ample support.

For there is nothing covered, etc. - God sees every thing; this is consolation to the upright and dismay to the wicked; and he will bring into judgment every work, and every secret thing, whether good or bad, Ecc 12:14.