v1 - the church is not Israel
v5 - a remnant has been preserved and only by God's grace. Has this remnant always held an absolutely true doctrine? No but God has used them
v11 - "fall" ? Stumbled, failed "transgressed" lay on the Sidelines.

Israel chose to turn away from God so God turned to Save the Gentiles and he planned it

(Eph 2 the word "as" means "to the same degree”)

v17 - the olive trees - one cultivated tended; another wild, useless

v22 - aspects of the character of God - goodness and severity --

v25 - do a word study on

'for I would not, brethren, that ye should be ignorant'
"mystery"
be aware -do not become proud because God chose us