Guard my mouth and keep me from violent traps

The first watch asked is over the speaker's own mouth

LORD, I cry unto thee: make haste unto me; give ear unto my voice, when I cry unto thee. Let my prayer be set forth before thee as incense; and the lifting up of my hands as the evening sacrifice. Set a watch, O LORD, before my mouth; keep the door of my lips. Incline not my heart to any evil thing, to practise wicked works with men that work iniquity: and let me not eat of their dainties.

Incense and evening sacrifice make the cry a liturgy. Then the danger named is not only their trap. It is my mouth, my lips, my heart, their dainties. The psalm is afraid of becoming the company it flees. Door of my lips is a guard asked from God, not a personality project only.

A righteous blow is welcomed; their net is not

Let the righteous smite me; it shall be a kindness: and let him reprove me; it shall be an excellent oil, which shall not break my head: for yet my prayer also shall be in their calamities. Keep me from the snares which they have laid for me, and the gins of the workers of iniquity. Let the wicked fall into their own nets, whilst that I withal escape.

Correction from the righteous is called kindness and oil, better than the feast of the wicked. Prayer continues even toward their calamities. Snares and gins are still real. Falling into their own nets is the hoped reversal, while the speaker escapes. The unit is not a dare to enjoy being hit, and it is not a permission to set the gin yourself.