Jesus Christ is the same yesterday and today and forever. -Heb 13:8 Here we see that Christ never Changes, speaking of his eternal qualities, certainly at some point the Son was without human form and the point of immaculate conception joined with human form, so we can see that some form of change occurred. So what is it the Hebrews passage is referring to? His attributes. Hebrews is using a description of him only used of Yahweh (Jehovah) God. God's divine attributes never changes. God alone never changes and remains the same forever. This is how he describes himself. Even his name "I Am" implies this. He said "I am the LORD, I do not change" in Malachi 3:6
Jesus being God the Son, is also called eternally unchanging, of course speaking of his divine attributes, since the Father, Son and Spirit are One God, all the same essence. I dislike inconsistency , I suppose because consistency is something about God that is so beautiful to me, and my hope is built on it. I myself have to work on being more consistently. So I am preaching much to myself here. Something we humans would do well to learn from God and to emulate, is his nature of consistent covenant love. We love to soak in the love of God and be it's benefactors, but God does not give us life and his deep love so that we keep it to ourselves. No, his Spirit is seen as a river of water; the water of life that is "flowing" from the throne, the very presence of God and reaching out to each one of us.
We are designed to be Holy Spirit living reservoirs, to allow other people to drink of Jesus Christ. This is what Jesus offered the woman at the well, and all who come to him. Now a dead stagnant lake has no outlet of what comes into it. But a living vibrant lake flows fresh water in and out. We must wisely learn to commit, out of love for God and others, to give and serve others like God does, as a covenant of love, that does not fail when the other party fails to keep up their expected part. True love is not just acting out of emotions and "flighty", but steadfastly gives. Emotional love is selfish, really to meet ones own feelings, but covenant love does what is right and keeps on giving with or without the fickle feelings. Let us be people of commitment to God and others faithfully month by month, day by day, serving like God serves us with consistency. I see so many flighty inconsistent Christians wanting to serve God out of sporadic emotions and have little to no unchanging consistency. God is consistent and unchanging. Let us be like your heavenly Father, and make wise loving covenants to serve and do so consistently . This changes lives here for eternity, as your reservoir of Holy Spirit living becomes pure as what God flows into you is consistently flowing life into others who need living water of God. The dead sea has nearly no life, because nothing is flowing out. Don't be like that, but Be alive for God. Have many outlets consistently flowing for his Spirit. This is holy and pleasing to God, this is living faithfully.