'My Covenant' in the Bible

My servant is truly blind, my messenger is truly deaf. My covenant partner, the servant of the Lord, is truly blind.

For the mountains may depart, and the hills be removed; but my lovingkindness shall not depart from thee, neither shall my covenant of peace be removed, saith Jehovah that hath mercy on thee.

For thus saith the LORD unto the eunuchs that keep my sabbaths, and choose the things that please me, and take hold of my covenant;

Also the sons of the stranger, that join themselves to the LORD, to serve him, and to love the name of the LORD, to be his servants, every one that keepeth the sabbath from polluting it, and taketh hold of my covenant;

As for me, this is my covenant with them, saith the LORD; My spirit that is upon thee, and my words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed, saith the LORD, from henceforth and for ever.