The word lion appears in a lot of passages in the Hebrew Bible. When you learn Biblical Hebrew you understand that one word in this beautiful language means and is translated differently according to the context. The word lion (Hebrew: אַרְיֵה) appears for the first time at the end of Genesis, when The Lord blessed Jacob's son and gave them the future to come, as written in Genesis 49:8-12-

" יְהוּדָה, אַתָּה יוֹדוּךָ אַחֶיךָ--יָדְךָ, בְּעֹרֶף אֹיְבֶיךָ; יִשְׁתַּחֲווּ לְךָ, בְּנֵי אָבִיךָ.  גּוּר אַרְיֵה יְהוּדָה, מִטֶּרֶף בְּנִי עָלִיתָ; כָּרַע רָבַץ כְּאַרְיֵה וּכְלָבִיא, מִי יְקִימֶנּוּ.  לֹא-יָסוּר שֵׁבֶט מִיהוּדָה, וּמְחֹקֵק מִבֵּין רַגְלָיו, עַד כִּי-יָבֹא שִׁילֹה, וְלוֹ יִקְּהַת עַמִּים.  אֹסְרִי לַגֶּפֶן עִירֹה, וְלַשֹּׂרֵקָה בְּנִי אֲתֹנוֹ; כִּבֵּס בַּיַּיִן לְבֻשׁוֹ, וּבְדַם-עֲנָבִים סוּתֹה.  חַכְלִילִי עֵינַיִם, מִיָּיִן; וּלְבֶן-שִׁנַּיִם, מֵחָלָב."

"Judah, thou art he whom thy brethren shall praise: thy hand shall be in the neck of thine enemies; thy father's children shall bow down before thee. Judah is a lion's whelp: from the prey, my son, thou art gone up: he stooped down, he couched as a lion, and as an old lion; who shall rouse him up? The sceptre shall not depart from Judah, nor a lawgiver from between his feet, until Shiloh come; and unto him shall the gathering of the people be. Binding his foal unto the vine, and his ass's colt unto the choice vine; he washed his garments in wine, and his clothes in the blood of grapes: His eyes shall be red with wine, and his teeth white with milk."

The lion is the sign of Judah, the tribe which David the king came from, the tribe which on its territory the temple was built.
The lion was also a symbol of the northern tribe Dan as we can read in Deuteronomy 33:24.  The next lion that we meet is the animal itself as we can see in Judges 14:5-6-

" וַיֵּרֶד שִׁמְשׁוֹן וְאָבִיו וְאִמּוֹ, תִּמְנָתָה; וַיָּבֹאוּ, עַד-כַּרְמֵי תִמְנָתָה, וְהִנֵּה כְּפִיר אֲרָיוֹת, שֹׁאֵג לִקְרָאתוֹ.  וַתִּצְלַח עָלָיו רוּחַ יְהוָה, וַיְשַׁסְּעֵהוּ כְּשַׁסַּע הַגְּדִי, וּמְאוּמָה, אֵין בְּיָדוֹ; וְלֹא הִגִּיד לְאָבִיו וּלְאִמּוֹ, אֵת אֲשֶׁר עָשָׂה."
 

"Then went Samson down, and his father and his mother, to Timnath, and came to the vineyards of Timnath: and, behold, a young lion roared against him. And the Spirit of the LORD came mightily upon him, and he rent him as he would have rent a kid, and he had nothing in his hand: but he told not his father or his mother what he had done"
 

The lion appears also as an animal in 1 Kings 13 as the keeper of the man of G-d who died due to his lack of confidence in the world of The Lord.
When the end of days will come the lion is going to be one of the animals that will enable the peace between animals and the human beings as written in Isaiah 11:6-9-

" וְגָר זְאֵב עִם-כֶּבֶשׂ, וְנָמֵר עִם-גְּדִי יִרְבָּץ; וְעֵגֶל וּכְפִיר וּמְרִיא יַחְדָּו, וְנַעַר קָטֹן נֹהֵג בָּם.  וּפָרָה וָדֹב תִּרְעֶינָה, יַחְדָּו יִרְבְּצוּ יַלְדֵיהֶן; וְאַרְיֵה כַּבָּקָר יֹאכַל-תֶּבֶן.  וְשִׁעֲשַׁע יוֹנֵק, עַל-חֻר פָּתֶן; וְעַל מְאוּרַת צִפְעוֹנִי, גָּמוּל יָדוֹ הָדָה.  לֹא-יָרֵעוּ וְלֹא-יַשְׁחִיתוּ, בְּכָל-הַר קָדְשִׁי:  כִּי-מָלְאָה הָאָרֶץ, דֵּעָה אֶת-יְהוָה, כַּמַּיִם, לַיָּם מְכַסִּים."
 

"The wolf also shall dwell with the lamb, and the leopard shall lie down with the kid; and the calf and the young lion and the fatling together; and a little child shall lead them. And the cow and the bear shall feed; their young ones shall lie down together: and the lion shall eat straw like the ox. And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice' den. They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the LORD, as the waters cover the sea."
According to Amos the lion is not just a sign for the power of a hero or an animal, but also to the power of G-d as we can see in Amos 3:8-
 

" אַרְיֵה שָׁאָג, מִי לֹא יִירָא; אֲדֹנָי יְהוִה דִּבֶּר, מִי לֹא יִנָּבֵא. "
 

"The lion hath roared, who will not fear? The Lord GOD hath spoken, who can but prophesy?"
 

In Daniel 6 the prophet who believed in G-d survived the king of animals as we can see in Daniel 6:17-25-

" בֵּאדַיִן מַלְכָּא אֲמַר, וְהַיְתִיו לְדָנִיֵּאל, וּרְמוֹ, לְגֻבָּא דִּי אַרְיָוָתָא; עָנֵה מַלְכָּא, וְאָמַר לְדָנִיֵּאל, אֱלָהָךְ דִּי אנתה (אַנְתְּ) פָּלַח-לֵהּ בִּתְדִירָא, הוּא יְשֵׁיזְבִנָּךְ.  וְהֵיתָיִת אֶבֶן חֲדָה, וְשֻׂמַת עַל-פֻּם גֻּבָּא; וְחַתְמַהּ מַלְכָּא בְּעִזְקְתֵהּ, וּבְעִזְקָת רַבְרְבָנוֹהִי, דִּי לָא-תִשְׁנֵא צְבוּ, בְּדָנִיֵּאל.  אֱדַיִן אֲזַל מַלְכָּא לְהֵיכְלֵהּ, וּבָת טְוָת, וְדַחֲוָן, לָא-הַנְעֵל קָדָמוֹהִי; וְשִׁנְתֵּהּ, נַדַּת עֲלוֹהִי.  בֵּאדַיִן מַלְכָּא, בִּשְׁפַּרְפָּרָא יְקוּם בְּנָגְהָא; וּבְהִתְבְּהָלָה--לְגֻבָּא דִי-אַרְיָוָתָא, אֲזַל.  וּכְמִקְרְבֵהּ לְגֻבָּא--לְדָנִיֵּאל, בְּקָל עֲצִיב זְעִק; עָנֵה מַלְכָּא וְאָמַר לְדָנִיֵּאל, דָּנִיֵּאל עֲבֵד אֱלָהָא חַיָּא--אֱלָהָךְ דִּי אנתה (אַנְתְּ) פָּלַח-לֵהּ בִּתְדִירָא, הַיְכִל לְשֵׁיזָבוּתָךְ מִן-אַרְיָוָתָא.  אֱדַיִן, דָּנִיֵּאל, עִם-מַלְכָּא, מַלִּל:  מַלְכָּא, לְעָלְמִין חֱיִי.  אֱלָהִי שְׁלַח מַלְאֲכֵהּ, וּסְגַר פֻּם אַרְיָוָתָא--וְלָא חַבְּלוּנִי; כָּל-קֳבֵל, דִּי קָדָמוֹהִי זָכוּ הִשְׁתְּכַחַת לִי, וְאַף קדמיך (קָדָמָךְ) מַלְכָּא, חֲבוּלָה לָא עַבְדֵת.  בֵּאדַיִן מַלְכָּא, שַׂגִּיא טְאֵב עֲלוֹהִי, וּלְדָנִיֵּאל, אֲמַר לְהַנְסָקָה מִן-גֻּבָּא; וְהֻסַּק דָּנִיֵּאל מִן-גֻּבָּא, וְכָל-חֲבָל לָא-הִשְׁתְּכַח בֵּהּ--דִּי, הֵימִן בֵּאלָהֵהּ.  וַאֲמַר מַלְכָּא, וְהַיְתִיו גֻּבְרַיָּא אִלֵּךְ דִּי-אֲכַלוּ קַרְצוֹהִי דִּי דָנִיֵּאל, וּלְגוֹב אַרְיָוָתָא רְמוֹ, אִנּוּן בְּנֵיהוֹן וּנְשֵׁיהוֹן; וְלָא-מְטוֹ לְאַרְעִית גֻּבָּא, עַד דִּי-שְׁלִטוּ בְהוֹן אַרְיָוָתָא, וְכָל-גַּרְמֵיהוֹן, הַדִּקוּ "
 

" Then the king commanded, and they brought Daniel, and cast him into the den of lions. Now the king spake and said unto Daniel, Thy God whom thou servest continually, he will deliver thee. And a stone was brought, and laid upon the mouth of the den; and the king sealed it with his own signet, and with the signet of his lords; that the purpose might not be changed concerning Daniel. Then the king went to his palace, and passed the night fasting: neither were instruments of musick brought before him: and his sleep went from him. Then the king arose very early in the morning, and went in haste unto the den of lions. And when he came to the den, he cried with a lamentable voice unto Daniel: and the king spake and said to Daniel, O Daniel, servant of the living God, is thy God, whom thou servest continually, able to deliver thee from the lions? Then said Daniel unto the king, O king, live for ever. My God hath sent his angel, and hath shut the lions' mouths, that they have not hurt me: forasmuch as before him innocency was found in me; and also before thee, O king, have I done no hurt. Then was the king exceedingly glad for him, and commanded that they should take Daniel up out of the den. So Daniel was taken up out of the den, and no manner of hurt was found upon him, because he believed in his God. And the king commanded, and they brought those men which had accused Daniel, and they cast them into the den of lions, them, their children, and their wives; and the lions had the mastery of them, and brake all their bones in pieces or ever they came at the bottom of the den"

As a Biblical Hebrew teacher it is really important for me to teach my student that a Hebrew word which looks identical and even translated the same could be understood with some meanings, as Daniel called from the den: "the king will live forever". This is the king of this world, G-d, and not the king of the animals, the lion!