Book of Joel Chapter 2 Vs. 27

 The Lord Had Pity

And ye shall know that I am in the midst of Israel, and that I am the LORD your God, and none else: and my people shall never be ashamed. Joel 2:27

And ye shall... The presence of God among his people shall be so manifest, the tokens of it so clear, that it shall be easily known. By the impressions of his love upon them; the teachings of his Spirit in them; the usefulness of the word and ordinances to them.

This return promised a reversal of the Lord’s departure (Ezekiel, chapter 8 to 11).

The spiritual and heavenly frame of soul they shall be favored with, and the pleasant taste of their conversation. This is the blessing Christ has promised to Gospel ministers and churches (Mat. 28:20).

and that I... That he is their covenant God and Father, and acknowledge none else.

and my people... Which is repeated for the certainty of it (see Joel 2:26).

Rev. 21:3 "And I heard a great voice out of heaven saying, Behold, the tabernacle of God [is] with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, [and be] their God."

The nation would also acknowledge (know) His active presence and His rightful place as their God (Joel 2:27). The words I am in Israel (lit., “I am in the midst of Israel”) recall the Pentateuchal references to God being “among” (or, “in the midst of”) His people (cf. Num. 11:20; 14:14; Deut. 7:21). The frequently used expression you will know that… I am the Lord your God also originated in the Pentateuch (cf. Exo. 6:7; 16:12). The association of that expression with the Lord’s exclusive claim to be Israel’s God (there is no other) reminds one of Deut. 4:35, 4:39. Through these allusions to earlier traditions, the Lord affirmed that His relationship to His people was just as vital then as it had been in Moses’ day.

The nation would also acknowledge (know) His active presence and His rightful place as their God (Joel 2:27). The words I am in Israel (lit., “I am in the midst of Israel”) recall the Pentateuchal references to God being “among” (or, “in the midst of”) His people (cf. Num. 11:20; 14:14; Deut. 7:21). The frequently used expression you will know that… I am the Lord your God also originated in the Pentateuch (cf. Exo. 6:7; 16:12). The association of that expression with the Lord’s exclusive claim to be Israel’s God (there is no other) reminds one of Deut. 4:35, 4:39. Through these allusions to earlier traditions, the Lord affirmed that His relationship to His people was just as vital then as it had been in Moses’ day.