‘Nevertheless many, even of the authorities, believed in (eis) him, but because they were afraid of the Pharisees they did not confess it in case they were put out of the synagogue, for they loved the praise of men more than the praise of God'.
The use of eis usually, but not always, signifies genuine faith in John's Gospel. There is therefore every reason to think that these were genuine believers, who would later reveal themselves. Yet at this point they were secret believers because they feared exclusion from the synagogue. Note that they included even some of those who were in authority. It sometimes takes time for believers to be willing to declare their position openly, but if they are true believers eventually they will.
‘They loved the praise of men more than the praise of God'. They could not bear to be unpopular or to be despised, or to be degraded or criticised by the Pharisees. Before we condemn them let us look at ourselves. Whose praise is most important to us? How glibly we can answer this question, but are we really sure?