Some say that the verse means that Jesus didn't keep a firm grasp on being equal with God,
He didn't have to keep a grasp on what is an unchangeable reality. Jesus always has been God's own Son, equal in character. Change of position of location does not change character. God can not change. Jesus, like our Father, can not change in His character which is God's character.
others say that Jesus didn't think of equality with God as something to steal,
He could not steal what already is His character of God.
and others say that Jesus didn't think of his equality with God as something he must steal.
Certainly, Jesus would not think He "must" . . . has to . . . steal something! He is God's own Son, not needing to steal anything which is good and right. Plus, it is impossible to steal what is God and what God is keeping.
So, I would say none of these above interpretations is correct.
What do you think?
Who, being in the form of God, thought it not robbery to be equal with God:
(Philippians 2:6 KJV)
He was equal to God, and He did not think it was robbery for Him to be so. In other words, Jesus did not steal His equality with God. But Satan tried to take over Heaven in order to be "God"; but Jesus always has been equal to God so there was no stealing that could be involved in Jesus being equal to God.
It was not robbery, and therefore it was right for Jesus to be equal with God. And yet, even though He did not hold an uprising in order to be equal with God . . . still He voluntarily left Heaven in order to come to us and reach us and save us.
But Satan did not come here voluntarily. Satan got thrown out.
So - - - this > I would say > is the interpretation that might be more helpful > how Jesus was worthy to be in Heaven and worshiped, but Jesus so superior and right was willing to leave Heaven in order to come here to people like us . . . to any and all evil and selfish people. And so - - - like Jesus . . . even if we are right with God, now . . . we, too, need to obey the example of Jesus by reaching to any and all nasty and awful people of this world . . . with hope like Jesus came with hope, for any person, at all >
love "hopes all things" (in 1 Corinthians 13:7).
"And walk in love, as Christ also has loved us and given Himself for us, an offering and a sacrifice to God for a sweet-smelling aroma." (Ephesians 5:2)