A pillar is a post that supports a building. This is a metaphor meaning important leaders. Alternate translation: "who were known to be important leaders" or "who were known to be important leaders of the church" (See: [[rc://en/ta/man/jit/figs-metaphor]])
This can be stated in active form. Alternate translation: "recognized the grace that God had given to me" (See: [[rc://en/ta/man/jit/figs-activepassive]])
The abstract noun "grace" can be translated with the phrase "be kind." Alternate translation: "that God had been kind to me" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])
Grasping and shaking the right hand was a symbol of fellowship. Alternate translation: "welcomed ... as fellow workers" or "welcomed ... with honor" (See: [[rc://en/ta/man/jit/translate-symaction]])