Sforno on Deuteronomy 4:34/ספורנו על דברים ד׳:ל״ד

1או הנסה אלוקים, even though G’d from time to time may have seen to it that certain people among the gentiles escaped what seemed like imminent disaster, such instances were limited to a few select individuals;

2במסות באותות, all of which proved that your good fortune was not due to some coincidence but had been planned by G’d.

3ובזרוע נטויה, ready to inflict further chastisements to demonstrate that that if the afflicted person did not respond with penitence You would continue to discipline him.