And Miriam and Aaron spake against Moses because of the Ethiopian woman whom
he had married: for he had married an Ethiopian woman. And they said, Hath
the LORD indeed spoken only by Moses? hath he not spoken also by us? And
the LORD heard it. (Now the man Moses was very meek, above all the men which
were upon the face of the earth.) And the LORD spake suddenly unto Moses, and
unto Aaron, and unto Miriam, Come out ye three unto the tabernacle of the
congregation. And they three came out. And the LORD came down in the pillar of the
cloud, and stood in the door of the tabernacle, and called Aaron and Miriam: and
they both came forth. And he said, Hear now my words: If there be a prophet among
you, I the LORD will make myself known unto him in a vision, and will speak unto him
in a dream. My servant Moses is not so, who is faithful in all mine house. With him
will I speak mouth to mouth, even apparently, and not in dark speeches; and the
similitude of the LORD shall he behold: wherefore then were ye not afraid to speak
against my servant Moses? And the anger of the LORD was kindled against them; and
he departed. And the cloud departed from off the tabernacle; and, behold, Miriam
became leprous, white as snow: and Aaron looked upon Miriam, and, behold, she
was leprous.

Numbers 12:1-10 (KJV)

Because of His covenant with Abraham, Isaac and Jacob, God committed Himself to
become their protector and defender, even to their descendants. Because of that He
did the mysterious wonders in Egypt to bring them out of the bondage. Also there is
a special divine commitment to defend those whom He has chosen and appointed
for a special task and assignment, much more when they serve faithfully.