If we have a latent state space $\mathbf{X}$ and the observations $\mathbf{Y}$ and the transition function between two states $\mathbf{x}_{t-1}$ and $\mathbf{x}_{t}$ is given by $\mathbf{f}$ which is a gaussian process with mean function $m_f$ and covariance $k_f$, where its graphical model is as follows: 

[![enter image description here][1]][1]

The generative model is given by
$$f(x)\sim\mathcal{GP}(m_f(\mathbf{x}),k_f(\mathbf{x},\mathbf{x}'))\\
\mathbf{x}_0\sim p(\mathbf{x}_0)\\
\mathbf{f}_t=f(\mathbf{x}_{t-1})\\
\mathbf{x}_{t}|\mathbf{f}_{t}\sim\mathcal{N}(\mathbf{f}_{t},\mathbf{Q})\\
\mathbf{y}_t|\mathbf{x}_t\sim p(\mathbf{y}_t|\mathbf{x}_t,\boldsymbol{\theta}_y)$$

I would like to know how the following probability can be rederived
$$\mathbf{f}_2|\mathbf{f}_1,\mathbf{x}_{0:1}\sim\mathcal{N}(\mathbf{f}_2|m_f(\mathbf{x}_1)+k_f(\mathbf{x}_1,\mathbf{x}_0)k_f(\mathbf{x}_0,\mathbf{x}_0)^{-1}(\mathbf{f}_1-m_f(\mathbf{x}_0)),k_f(\mathbf{x}_1,\mathbf{x}_1)-k_f(\mathbf{x}_1,\mathbf{x}_0)k_f(\mathbf{x}_0,\mathbf{x}_0)^{-1}k_f(\mathbf{x}_0,\mathbf{x}_1))$$
Thanks!

  [1]: https://i.sstatic.net/a6ME1.png