Solidarity is different than Unity in that Solidarity implies action as well as Agreement.
Satan is more interested in Action than agreement. God is more interested in Agreement but He expects Action to follow Agreement.
Fellowship and Peace are the products of Unity in Agreement.
A common purpose or objective and determination is indicatuve of Solidarity.
Now, it is apparent that Solidarity is not a bad thing even though it is not as high in order as Unity.
James critizes Faith without Works. He sees that as a manifestation of shallowness and a lack of commitment.
In the same sense Unity without Solidarity is a sign of shallowness snd lack of commitment.
Christianity has to have Unity because of the HolySpirit who unifies us. A lack of Unity indicates a lack of appreciation for the HokySpirit.
But Christianity must have Solidarity if it is going to defeat its Social and Political opponents.
We must agree on the goals we have for our Society recognizing that it is impossible to force people to Receive Christ Jesus.
The TenCommandments provided a Spiritual compass which was ignored by many in Israel. However, the Social compass that it provided was important for establishing order in Israel enabling it to become a successful nation with common values.
Two short-term goals which would help us correct the ship would be to eliminate false witnessing and stealing. False witnessing is Lying, spinning and telling half-truths. Stealing is robbery, fraud, and unreasonable/overbearing taxation.
Can we stand in Solidarity for these goals?
20211019 update
Compulsary Vaccination involving an experimental non-FDA-approved Vaccine whose efficacy is questionable and whose side-effects are unknown is illegal and immoral.
Those who value their right to make personal choices about their Health and Speech while remaining Free to work and move in Society without being stigmatized and penalized for their choices must stand in Solidarity against Fascism wherever it manifests.
This means we must be willing to suffer the short-term Consequences for refusing to surrender our rights.
Those who are penalized must be supported by the rest of us.