“Some people believe that Jesus was an avatar, or divine being, who came to Earth to teach humanity about love and peace. Others believe that Jesus was a great teacher and prophet, but not an avatar. Still others believe that Jesus was simply a man who lived and died like any other. Ultimately, what each person believes about Jesus is a matter of faith.”
“Because it is a mythical term, it can be perfect or imperfect in the theology of avatar. As a theologian, Dr. Paul David Tripp claims, the term “avatar” refers to Hindu mythology rather than Christian theology. The figure is referred to as a messenger or god in Hinduism in order to benefit others. The term ‘incarnation’ is used in Christian theology to describe the arrival of Jesus Christ into the world. In the flesh, Jesus was imperfect and made mistakes. He is also the perfect God, in addition to being God in the flesh.”
https://debatingchristianity.com/forum/viewtopic.php?p=1129928#p1129928
Vishnu takes avatar (incarnation) whenever needed as said in Gita “Yada Yada Hi Dharmasya Glanirva Bhavathi Bharatha, Abhyuthanam Adharmaysya Tadatmanam Srijami”.
https://debatingchristianity.com/forum/viewtopic.php?p=1130024#p1130024
Whenever there is decay of righteousness, O Bharata, and there is exaltation of unrighteousness, then I Myself come forth;
For the protection of the good, for the destruction of evil-doers, for the sake of firmly establishing righteousness, I am born from age to age.
https://debatingchristianity.com/forum/viewtopic.php?p=1130122#p1130122