i Register
In some senses, obtest is marked as archaic. Watch for register when choosing this word.
verb
To implore, beseech, plead, beg.
To call on a witness (often God) to confirm that something is true.
Now Suppliants, from Laurentum ſent, demand A Truce, with Olive Branches in their hand. Obteſt his Clemency, and from the Plain Beg leave to draw the Bodies of their ſlain.