It is sanctified (αγιαζετα). Present passive indicative of αγιαζω, here "rendered holy" rather than "declared holy." Cf. verse 1. Timothy 4:4.

Through the word of God and prayers (δια λογου θεου κα εντευξεως). See 1. Timothy 2:1 for εντευξις. Paul seems to refer to Genesis 1. It is almost a hendiadys "by the use of Scripture in prayer."