Sakinah is an important word and a very important concept in both Islamic and Jewish thought.
In Islamic thought, it refers to the tranquility, serenity and peace of mind that results when a believer becomes totally aware of God’s near by presence. Although Sakinah dwells in the heart of one who is already a sensitive and faithful believer; it now comes to him or her directly from God’s close presence and personal interest; to confirm and strengthen that believer’s faith.
As the Qur’an says “It is God who sent down tranquillity into the hearts of the believers, that they would increase in faith along with their (present) faith.” (48:4)
Thus, the experience of Sakinah is both God’s gift of enhanced, confirming faith and the product of one’s own faithfulness. (Qur’an 9:26 & 40)
This is clearly stated in the example given in the Qur’an about Prophet Samuel’s (a) selection of Saul to be the first King of Israel.
“Their prophet (Samuel) said to them (The People of Israel), “Indeed, a sign of his (Saul’s) kingship is that the chest (ark of the covenant) will come to you in which is Sakinah- assurance (Ghali translates; serenity) from your Lord, and a remnant of what the family of Moses and the family of Aaron had left (the ten commandments’ stone tablets), carried by angels. Indeed, in that is a sign for you, if you are (already) believers.” (2:248)
Jewish tradition asserts that Torah scholars may experience a Shekinah blessing during study, Rabbi Chananiah ben Teradion said, ‘when two sit together and words of Torah pass between them, the Shekinah dwells between them’ . . , (Mishnah Avot 3.3)
Community prayer is also a place where one can experience Shekinah as Talmud B’rachot 6a says: “Whenever ten (or more) are gathered for prayer, there the Shekinah dwells.”
The Sakinah can also dwell in a sacred object like the ark of the covenant or in a lowly bush (Qur’an 2:248). Those who are  truly “Blessed by the Lord…with the best gifts of the earth and its fulness, and the favor of Him who dwells in the bush”. (Deuteronomy 33:16)
The Sakinah can also dwell on or in a holy person; a saint, a sage. or a Prophet like Muhammad (s): “Allah sent down His Sakinah (tranquillity) upon His Messenger and upon the believers and imposed upon them the word of righteousness, and they were more deserving of it and worthy of it. (Qur’an 48: 26)
However, the word/concept Shekinah in Jewish rabbinic thought is also a name for God that focuses mostly on the presence of God that may manifest itself during several types of ordinary religious activities such as the prayer and Torah study already referred to; and also when visiting the sick (Shabbat 12b). practicing hospitality (Shabbat 127a & Sanhedrin 103b), giving charity (Baba Batra 10a), practicing chastity before marriage (Derek Ereẓ i.) and faithfulness within marriage (Soṭah 17a).
It is true that doing all these things frequently will help produce greater faith, confidence, and peace of mind. But the Jewish focus is more on the opportunity to personally experience God’s presence in a daily activity, than on an individual’s personal spiritual growth.
This somewhat different emphasis between Sakinah and Shekinah are not opposites. They are simply two different perspectives: like seeing a lion from the front, or from the side. Sakinah and Shekinah thus compliment each other; and proclaim the interactive reciprocities between humans love of God and God’s love of humans.
From another perspective, Shekinah, a rabbinic name for God, shifts the view from the community to the individual’s experience, just as Sakinah shifts the focus from Jihad (both military and personal effort) to calmness, serenity and effortless peace of mind. Both of these shifts are complementary; not contradictory,
The connection between our faithfulness and God’s Shekinah is described in Exodus 25; when God directs the People of Israel to build a sanctuary. But first God says, each person should make a voluntary offering: “The Lord said to Moses “Tell the Israelites to bring me an offering. You are to receive an offering for me, from everyone whose heart prompts them to give.” (Exodus 25:1-2)
Six verses later God says,“Then have them make a sanctuary for me, and I will dwell (Shekanti) among them.” (25:8)  First humans choose to make a heart felt offering to God; then God chooses to dwell among, and within, faithful humans and their religious communities.
When God is well pleased by faithful people, God’s gift of inner peace and reassurance is sent down to them. As it is written: “Certainly Allah was pleased with the believers when they pledged allegiance to you, (Muhammad), under the tree, and He knew what was in their hearts, so He sent down Sakinah (tranquillity) upon them and rewarded them with an imminent conquest”. (Qur’an 48:18)