There is but a step between me and death - My life is in the most imminent danger. Your father has, most assuredly, determined to destroy me.
The same figure used here, there is but a step between me and death, may be found in Juvenal, who, satirizing those who risk their lives for the sake of gain in perilous voyages, speaks thus: -
I nune et ventis animam committe, dolato
Confisus ligno, digitis a morte remotus
Quatuor aut septem, si sit latissima teda.
Sat. xii., ver. 57.
"Go now, and commit thy life to the winds,
trusting to a hewn plank, four or seven fingers thick,
if the beam out of which it has been cut have been large enough."
And David sware moreover - Rather, “yet again.” He met Jonathan‘s denial by repeating his statement and confirming it with an oath.