Safety is built in stages.
Timothy R. Clark describes four stages of psychological safety. Each one builds on the one before, and you can't skip to challenge.
1 · Inclusion
“I Belong Here.”
- Accepted for who you are
- Invited in, not just allowed in
2 · Learner
“I Can Ask And Fail.”
- Questions are welcome
- Mistakes are treated as learning
3 · Contributor
“My Work Counts.”
- Trusted to add real value
- Given autonomy and a voice
4 · Challenger
“I Can Question How We Do Things.”
- Safe to challenge the status quo
- Even when the boss likes it
Source: LeaderFactor ↗
Include, invite, then welcome the challenge.