Radak

Bulls have surrounded me: – This is the trouble that is near at hand, that bulls have compassed me – a figure for lusty and powerful and wicked enemies. The interpretation of (רבים is) mighty (ones): – that is, great in strength. So also strong ones of Bashan: – Bashan is a district in the land of Israel, a district of fat and rich pasture, and the cattle that feed there are fat and strong. He compares the wicked enemies with them. And so it says (Amos 4:1) in a figure “kine of Bashan” with reference to the women who oppress the poor, who crush the needy. have beset me around (כתרוני): – equivalent to have surrounded me; just as the crown (כתר) surrounds (encircles) the head. And so we have (Judges 20:43): “they beset (כתרו) Benjamin around.”