Oh yeah, safety first.
I do this for a living as a mobile mechanic every day.
Always use jack stands and wheel chalks, level hard pavement or large wood planks for a flat base under the jack and jackstand if working on dirt.
Never trust a floor jack regardless how beefy it is.
I had one brand new in the box, jack fail right before I slid the jackstand under it.
A couple more seconds earlier and I would have had a crushed skull.