O believers! Do not make friendship with those who are enemies of Mine and yours. Would you show them friendship, when they have denied the truth that has come to you and have driven the Prophet and yourselves out of your homes, simply because you believe in Allah, your Lord? If it was indeed to strive in My way, and to seek My good pleasure that you left your homes, how can you befriend in secret? I know all that you conceal, and all that you reveal. Any of you who does this, he indeed has gone astray from the Right Way.
Meaning:-
Conceal: to hide, to keep secret, to prevent or avoid disclosing, keep secret.
Astray: into error, away from the correct path or direction.